Explore the core architecture of the operating system, including the kernel, memory management, and process scheduling.

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macOS26: MenuBarExtra item not showing
Hi, In macOS26 beta, our app icon is not showing anymore in the MenuBar. It is also not displayed in the new section "Menu Bar > Allow in the Menu Bar", which seems to be the way to show/hide Menu Bar icons in macOS 26. The icon is correctly displayed and working in macOS 15. Our app is signed and notarized. It also has the "LSUIElement" value set to "true" in the Info.plist file. Is there some new mandatory entitlements to add in order to have our app showing in the "Allow in the Menu Bar" section? Thanks in advance for your help. Regards
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Nov ’25
autologin required inconsistent for virtualization
Hi, I have two issues going on: Creation of macOS VMs requires autologin is enabled: Mon Apr 13 11:27:18 20 anka.log (ankahv) 511: pid 511: installing /Users/veertu/Library/Application Support/Veertu/Anka/img_lib/UniversalMac_15.6.1_24G90_Restore.ipsw... Mon Apr 13 11:27:20 40 anka.log (install) 511: (null): installation failed: Error Domain=VZErrorDomain Code=10007 "The virtual machine failed to start." UserInfo={NSLocalizedFailure=An error occurred during installation., NSLocalizedFailureReason=The virtual machine failed to start., NSUnderlyingError=0xca2c0ced0 {Error Domain=VZErrorDomain Code=-9 "The virtual machine encountered a security error." UserInfo={NSLocalizedFailure=Unable to access security information., NSLocalizedFailureReason=The virtual machine encountered a security error., NSUnderlyingError=0xca3029320 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo={NSLocalizedFailureReason=Failed to get current host key., NSUnderlyingError=0xca30292f0 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo=0xca2a88040 (not displayed)}}}}}} Mon Apr 13 11:27:20 40 anka.log (install) 511: (null): virtual machine stopped with error: Error Domain=VZErrorDomain Code=4 "Transition from state “error” to state “stopping” is invalid." UserInfo={NSLocalizedFailure=Invalid virtual machine state transition., NSLocalizedFailureReason=Transition from state “error” to state “stopping” is invalid.} Mon Apr 13 11:27:20 40 anka.log (install) 511: failed to install macOS: Error Domain=VZErrorDomain Code=10007 "The virtual machine failed to start." UserInfo={NSLocalizedFailure=An error occurred during installation., NSLocalizedFailureReason=The virtual machine failed to start., NSUnderlyingError=0xca2c0ced0 {Error Domain=VZErrorDomain Code=-9 "The virtual machine encountered a security error." UserInfo={NSLocalizedFailure=Unable to access security information., NSLocalizedFailureReason=The virtual machine encountered a security error., NSUnderlyingError=0xca3029320 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo={NSLocalizedFailureReason=Failed to get current host key., NSUnderlyingError=0xca30292f0 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo=0xca2a88040 (not displayed)}}}}}} Running a macOS 26.x VM fails for similar reasons, yet running a 15.x VM works fine: Mon Apr 13 11:20:10 20 0f5d4fe7-edac-4f6d-aebb-f185702f2c25.log (ankahv) 474: pid 474: session started on host 26.4.1 Mon Apr 13 11:20:10 40 0f5d4fe7-edac-4f6d-aebb-f185702f2c25.log (ankahv) 474: 0f5d4fe7-edac-4f6d-aebb-f185702f2c25: failed to start: Error Domain=VZErrorDomain Code=-9 "The virtual machine encountered a security error." UserInfo={NSLocalizedFailure=Unable to access security information., NSLocalizedFailureReason=The virtual machine encountered a security error., NSUnderlyingError=0x76f049e00 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo={NSLocalizedFailureReason=Failed to get current host key., NSUnderlyingError=0x76f049e60 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo={NSLocalizedFailureReason=Failed to create new HostKey., NSUnderlyingError=0x76f049dd0 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo=0x76ec49d60 (not displayed)}}}}}} Mon Apr 13 11:20:10 40 0f5d4fe7-edac-4f6d-aebb-f185702f2c25.log (ankanet) 474: failed to receive packets: Connection reset by peer This is super painful for us to manage since some of our users can't have autologin enabled (like major banks under strict MDM requirements). Or, AWS EC2 Macs which have no VNC enabled at all by default. What's the trick here to make sure we can consistently use virtualization without autologin?
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323
Apr ’26
macOS 26.1 – Severe lag in Open/Save panels when iCloud Drive root contains any items (FileProvider v3 regression)
I’ve filed this as FB20943098 (macOS 26.1 – FileProvider v3 synchronous enumeration bug), but posting here in case others can reproduce and add duplicates. Systems: macOS 26.1 (26B82) M4 Mac mini Pro and M4 MacBook Air Symptoms: In any app (TextEdit, Pages, Browsers, etc.), the Open/Save dialog lags for ~1s per folder navigation click. CPU spikes from fileproviderd, cloudd, bird, and siriactionsd. Key discovery: If my iCloud Drive root is empty (only “Documents” and “Downloads”), performance is perfect. As soon as any folder or file exists at the root of iCloud Drive, the lag returns immediately. Moving those items into “Documents” or “Downloads” makes everything smooth again. Analysis: Based on process traces and container paths, this appears to originate in the FileProvider.framework subsystem (via fileproviderd), which mediates iCloud Drive. Early evidence suggests that folder enumeration of the iCloud Drive container root may be blocking UI threads in macOS 26.1. I believe this may be related to the recent internal migration of the file-provider backend (often referred to as “v3”), but I do not have direct confirmation from Apple of that exact change. MacOS 26.1’s new FileProvider v3 backend seems to be blocking the Open/Save panel while enumerating the iCloud Drive root container (~/Library/Application Support/FileProvider/723EBBFF-…). Folder enumeration seems to wait synchronously for metadata from fileproviderd, and if the local SQLite DB is busy (WAL writes or sync state checks), UI freezes briefly. Workarounds: Disabling iCloud Drive entirely fixes the issue. Simply disabling Desktop/Documents sync does not help. Keeping the iCloud Drive root empty avoids the lag without turning iCloud off. I am able to store whatever I please in the Desktop or Documents folder which is currently syncing. Would appreciate if others on 26.1 could confirm. Engineers: I’ve attached fs_usage, log stream, and process samples to my Feedback ticket via the FB20943098. Expected behavior: Folder enumeration in NSOpenPanel should remain asynchronous regardless of FileProvider background activity. Open/save modal should be responsive and smooth.
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1.6k
Nov ’25
AccessorySetupKit documentation
This is not a question but rather a small bit of documentation on how Accessory Setup Kit actually works. I spent a couple days figuring this out so I thought let's share my findings. The example app is very light and the documentation definitely has room for improvement so here are a couple important notes. Findings: If you're running > iOS 18 and add any property to your Info.plist file you're no longer able to scan for devices by using CBCentralManager.scanForPeriphals. This will no longer return discoverable devices. Below iOS 18 these properties in the Info.plist are ignored by the OS and you can safely use the "legacy" method of connecting to bluetooth devices. If you're running > iOS 26 the removeAccessory will show a prompt to the user. If you're running < 26 you can silently remove the accessory and start each session with a clean state. If you create CBCentralManager before you start the ASK session you'll not get the state = PoweredOn. If you have 0 accessories connected to your application CBCentralManager will never enter the state = PoweredOn when you create the CBCentralManager. Pre-ASK this would be the trigger for iOS to ask the user permission. This is no longer necessary with ASK. If you have have 1 or more accessories authorized to your app this will be returned in the session.accessories after the session has started. This is an important indicator to determine app behavior. If you have 1 or more accessories CBCentralManager.scanForPeripherals will ONLY return previously authorized AND discoverable devices. Use this for when you want to connect to a previously authorized device. If you have 1 or more accessories and the CBCentralManager.scanForPeripherals returns nothing you can (safely) assume the user attempts to onboard a new device. So for my application I take the following steps: Check for iOS version, if > iOS 18 start ASK session. Are there previously authorized devices? -- yes: run CBCentralManger.scanForPeripherals -- no: show the picker Did the scan return any devices? -- yes: show UI to select device or connect with first available device in the list -- no: show the picker Feel free to add any of your findings and @Apple please update the documentation!
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828
Jan ’26
Bluetooth connection unexpectedly timing out with macOS Sequoia
After the macOS Sequoia update, my app seems to have an issue with Bluetooth communication between macOS and iOS that uses CoreBluetooth for Central-Peripheral communication. Setup: The iPhone (in my case: iPhone 14 Pro with iOS 18.0 (22A3354)) acts as the Central, and the Mac (in my case: 14" MacBook Pro 2023 with macOS 15.0 (24A335)) as the Peripheral. I’ve implemented a mechanism where the Central (iPhone) sends a message to the Peripheral (Mac) every 15 seconds to keep the connection alive (Because it needs to wait for notify characteristic updates). I never noticed this kind of issue before, but with macOS Sequoia I get it permanently. Issue: The connection drops unexpectedly after a period of time (sometimes 20 seconds, sometimes a few minutes) with CBErrorDomain - code 6: The connection has timed out unexpectedly. Sample Code: Peripheral (Mac): ContentView (Peripheral).txt ContentViewModel (Peripheral).txt Central (iPhone): ContentView (Central).txt ContentViewModel (Central).txt Reproduce: I attached sample code including the Central-Sample (for iPhone) and Peripheral-Sample (for Mac). Just run the Peripheral-Sample (after granting Bluetooth permissions). Then run the Central-Sample and select the Mac device in the list After selecting it should connect, discover the service & characteristic and should start writing messages to it. After some time the func centralManager(_ central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: (any Error)?) {should get called with timed out unexpectedly error. Could anyone please look into this issue and advise on whether there’s a known bug or any workaround? Any guidance would be greatly appreciated, as this impacts the stability of Bluetooth communication between the devices. Thanks in advance. Logs: I also ran the console.app during this issue which got these errors (if this is helpful): console_logs.txt
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3.6k
Oct ’25
Behavior of Bookmark URLs and Files App Recently Deleted – Clarification and Potential Bug
I am developing an iOS/iPadOS application and have encountered some behavior regarding Files App and security-scoped bookmarks that I would like to clarify. Additionally, I would like to report some behavior which might include a potential issue. Question1: Accessing deleted files via bookmark (Specification clarification) Our app saves file URLs as bookmarks, which file that user has selected on Files App or app-created so to open a file which user has modified previously in the next launch. When a user deletes a file in Files App (moves a file to Recently Deleted), the app can still resolve the bookmark and access the file for read/write operations. Is this behavior intended? In other words, is it correct that a bookmark can access a file that has been deleted in Files App but not permanently removed? Question2: Overwriting a file in Recently Deleted (Potential bug) We noticed that overwriting a file in Recently Deleted behaves differently depending on the method used. Current implementation 1.Create a temporary file in the same directory 2.Write content to the temporary file 3.Delete the original file ([NSFileManager removeItemAtURL:error:]) 4.Move the temporary file to the original file path ([NSFileManager moveItemAtURL:toURL:error:]) Result: The file disappears from Files App Recently Deleted. In contrast, using [NSFileManager replaceItemAtURL:withItemAtURL:] keeps the file visible in Recently Deleted. Is this difference designed behavior? If not, this may be a bug. Question3: Detecting files in Recently Deleted We want to detect whether a file resides in Recently Deleted, but we cannot find a reliable and officially supported method. Recently Deleted files appear under .Trash, but using the path alone is not a reliable method. We have tried the following APIs without success: [NSURL getResourceValue:forKey:NSURLIsHiddenKey error:] [NSURL checkResourceIsReachableAndReturnError:] [NSFileManager fileExistsAtPath:] [NSFileManager isReadableFileAtPath:] [NSFileManager getRelationship:ofDirectory:NSTrashDirectory inDomain:NSUserDomainMask toItemAtURL:error:] We could not obtain the Recently Deleted folder URL using standard APIs. [NSFileManager URLsForDirectory:NSTrashDirectory inDomains:NSUserDomainMask] [NSFileManager URLForDirectory:NSTrashDirectory inDomain:NSUserDomainMask appropriateForURL:url create:error:] Could you advise a safe and supported way to detect Recently Deleted files properly by the app?
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398
Mar ’26
iOS App Crashes after install but not when running from Xcode
I have an odd issue I'm trying to troubleshoot. I have an app that is deployed to our enterprise and works on almost all of our devices. Lately, I have devices (very small number) where the app installs from our MDM and it crashes upon launch, it does not get past the launch screen. If I remove and reinstall the app from the MDM it still crashes. I decided to put the devices in developer mode and if I run the App from Xcode on the device it works fine. If I stop it and run it right from the device it also works. If I do a final build of the app and install it using "Devices and Simulators", the app crashes upon launch. Using "Devices and Simulators" I check for crash log for the app and no file. I am stumped as to whats going on.
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252
Oct ’25
Feature Proposal: CrossRun
Hi everyone! I've considered this — what if Apple added a native system-wide feature in all of iOS, iPadOS, and macOS called “CrossRun” where you can natively execute non-App Store software like Windows or Linux apps natively on your device? But not in a sluggish emulator—this would use intelligent Apple-signed Just-In-Time (JIT) compilation inside the virtual containers, and the experience would actually perform fast and feel natural. This is my vision for CrossRun: Every developer, student, creative professional, and enterprise user who relies on specialized software—whether it’s legacy Windows tools, Linux-only applications, or vintage DOS and Classic Mac utilities—feels the pain of platform lock‑in. Artists can’t run niche Linux‑based graphics programs on their iPads. Engineers can’t test x64‑only binaries on Apple Silicon without juggling emulators. Retro‑gaming fans miss their favorite DOS titles. Even enterprises struggle to standardize on Apple hardware because critical Windows‑only applications won’t run seamlessly. If we don’t push for CrossRun now, the Apple ecosystem remains siloed: iPads and iPhones will continue limited to App Store apps, Macs will still need multiple third‑party VM tools, and countless workflows stay fragmented across devices. That means slower development cycles, extra licensing costs for virtualization software, and lost opportunities for education, creativity, and business efficiency. Without CrossRun’s universal runtime, we’ll still be rebooting into different environments or paying for separate virtualization apps—year after year. Apple already provides the building blocks: Rosetta 2, Virtualization.framework, Apple Silicon—and QEMU thrives as open‑source, battle‑tested code. With the next wave of Apple Silicon devices on the horizon, demand for cross‑architecture support, legacy‑app compatibility, and enterprise containerization is only growing. Delaying another year will cost developers, businesses, and users real time and money. Let’s show Apple that the community is ready for a truly universal, system‑integrated solution—right now. Key features we should demand in CrossRun: Built‑in Apple‑signed QEMU for all ISAs (x86, ARM, RISC‑V, PowerPC, 68k, MIPS, etc.) Rosetta 2 JIT for seamless macOS and Windows x64 support Metal‑backed 3D GPU passthrough and Vulkan→Metal / Direct3D→Metal translation Downloadable OS and app containers via the App Store or verified repositories (Ubuntu, Windows ARM/x64, Android, Haiku, ReactOS, FreeBSD, retro OSes) Predictive ML pre‑warm cache to speed cold starts Dynamic resource scaling (CPU, GPU, RAM) per container iCloud‑synced snapshots and shareable VM links for cross‑device continuity Customizable on‑screen controls (D‑pad, virtual buttons, trackpad, keyboard) on iPhone, iPad, and macOS Secure sandboxing via Virtualization.framework with VM disk encryption and MDM policy enforcement Virtual LAN and VPN passthrough for container networking Developer tooling (crossrunctl CLI, Xcode debugger integration, CI/CD support) Plugin ecosystem and container SDK for community‑published templates and translation layers Let Apple know it’s time to bake CrossRun into the system and unlock a universal runtime for every app, past and future, across iOS, iPadOS, and macOS.
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273
Jul ’25
KDK for current stable version (26.1) missing
The current stable macOS version, 26.1 (build 25B78) is missing a corresponding Kernel Debug Kit (KDK) on the developer downloads page. This means I can't do any kernel-level development tasks currently. For example, if I try to build a new kernel collection with kmutil I get the message Missing Developer Kit: As of macOS 13.0, you will need to install a KDK matching your build 25B78 to rebuild kernel collections. but there is no build 25B78 KDK available to download. The latest 26.1 KDK on the download page is 25B5062e (from a beta I believe) and the final stable KDK for build 25B78 (which kernel development tools require) was never published. Is there any workaround for this to correctly do kernel-level development targeting the latest stable release, or a timeline for when the KDK will release? Thanks!
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522
Nov ’25
CBCentralManager State Changes to PoweredOff After Using ASK for Accessory Setup
We are observing some unexpected behavior in our app when using ASK. Our app is able to successfully discover and set up an accessory via ASK. After the setup completes, the connection to the accessory is managed through CBCentralManager and works as expected. However, when we attempt to discover another accessory afterward, the picker is shown and indicates that accessory discovery is in progress. After approximately 10 seconds, the CBCentralManager delegate reports the Bluetooth state as poweredOff. Once this happens, the state never transitions back to poweredOn. At this point, the only way to reconnect to the device or continue discovery is to relaunch the app. We are wondering if anyone else has encountered similar behavior, or if this is a known or documented limitation/behavior when using ASK in combination with CBCentralManager.
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770
Feb ’26
Timed-Wait for main thread
The scenario is, in a macOS app (primarly), main thread needs to wait for some time for a certain 'event'. When that event occurs, the main thread is signaled, it gets unblocked and moves on. An example is, during shutdown, a special thread known as shutdown thread waits for all other worker threads to return (thread join operation). When all threads have returned, the shutdown thread signals the main thread, which was waiting on a timer, to continue with the shutdown flow. If shutdown thread signals the main thread before the later's timer expires, it means all threads have returned. If main thread's timer expires first, it means some threads have failed to join (probably stuck in infinite loop due to bug, disk I/O etc.). This post is to understand how main thread can wait for some time for the shutdown thread. There are two ways: a) dispatch_semaphore_t b) pthread conditional variable (pthread_cond_t) and mutex (pthread_mutex_t). Expanding a bit on option (b) using conditional variable and mutex: // This method is invoked on the main thread bool ConditionSignal::TimedWait() noexcept { struct timespec ts; pthread_mutex_t * mutex = (pthread_mutex_t *) (&vPosix.vMutexStorage[0]); pthread_cond_t * cond = (pthread_cond_t *) (&vPosix.vCondVarStorage[0]); // Set the timer to 3 sec. clock_gettime(CLOCK_REALTIME, &ts); ts.tv_sec += 3; pthread_mutex_lock(mutex); LOG("Main thread has acquired the mutex and is waiting!"); int wait_result = pthread_cond_timedwait(cond, mutex, &ts); switch (wait_result) { case 0: LOG("Main thread signaled!"); return true; case ETIMEDOUT: LOG("Main thread's timer expired!"); return false; default: LOG("Error: Unexpected return value from pthread_cond_timedwait: " + std::to_string(wait_result)); break; } return false; } // This method is invoked on shutdown thread after all worker threads have returned. void ConditionSignal::Raise() noexcept { pthread_mutex_t * mutex = (pthread_mutex_t *) (&vPosix.vMutexStorage); pthread_cond_t * cond = (pthread_cond_t *) (&vPosix.vCondVarStorage); pthread_mutex_lock(mutex); LOG("[Shutdown thread]: Signalling main thread..."); pthread_cond_signal(cond); pthread_mutex_unlock(mutex); } Both options allow the main thread to wait for some time (for shutdown thread) and continue execution. However, when using dispatch_semaphore_t, I get the following warning: Thread Performance Checker: Thread running at User-interactive quality-of-service class waiting on a lower QoS thread running at Default quality-of-service class. Investigate ways to avoid priority inversions Whereas, with conditional variables, there are no warnings. I understand the warning - holding the main thread can prevent it from responding to user events, thus causing the app to freeze. And in iOS, the process is killed if main thread takes more than 5 secs to return from applicationWillTerminate(_:) delegate method. But in this scenario, the main thread is on a timed-wait, for some milliseconds i.e., it is guaranteed to not get blocked indefinitely. While this is described for macOS, this functionality is required for all Apple OSes. What is the recommend way?
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155
Feb ’26
How to mount custom FSKit-based file system in Finder?
Hi, I'm working with the new FSKit framework and have successfully implemented a custom file system using FSUnaryFileSystem. Mounting the file system via Terminal works perfectly — I can create, delete, and browse files and directories as expected. Since /Volumes is protected on modern macOS systems, I cannot mount my file system there directly. Instead, I mount it into a different writable directory (e.g., /tmp/MyFS) and then create a symbolic link to it in a user-visible location such as ~/Downloads/MyFS. Finder does see the symlink and displays it with a "Volume" icon, but clicking it results in an error — it cannot be opened. It seems like Finder does not treat the symlinked mount as a fully functional volume. Is there a proper way to register or announce a FSKit-mounted file system so that Finder lists it as a real volume and allows access to it? Are there additional steps (APIs, notifications, entitlements, or Info.plist keys) required to integrate with Finder? Any insight would be greatly appreciated. Thanks!
4
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397
Jun ’25
Monitor mode capture broken with Wi-Fi 7 (M5 Pro MacBook Pro) on macOS 26 - worked previously on same OS with older hardware
Platform: macOS 26.3.1, M5 Pro MacBook Pro Framework: CoreWLAN Affected applications: NetViews, Air Tool 2, and our own tooling — appears to be specific to the new Wi-Fi 7 hardware Hardware Card Type: chip id: 0x11 api 1.2 firmware [Rev 72.11.260 N1B1 devFused=0] phy [17.1.17.0], core80211 [324.10.260 N1_silicon_b] Firmware: Jan 27 2026 21:18:32 version XBS_BUILD_TAG GIT_DESCRIBE FWID chip id: 0x11 api 1.2 firmware [Rev 72.11.260 N1B1 devFused=0] phy [17.1.17.0], core80211 [324.10.260 N1_silicon_b] Driver: IO80211_driverkit-1540.16 "IO80211_driverkit-1540.16" Jan 27 2026 Background Both issues described below were working correctly on macOS 26 with previous-generation hardware. The regression is specific to the Wi-Fi 7 card shipping in the M5 Pro MacBook Pro. This is not an OS regression — it is a hardware/driver/firmware compatibility issue with the new card under macOS 26. Issue 1: disassociate() + tcpdump/Wireshark -I no longer enters monitor mode Previously, the standard approach of calling disassociate() and then launching tcpdump -i en0 -I or Wireshark -i en0 -I -k would successfully put the interface into monitor mode. On the M5 Pro Wi-Fi 7 card, this no longer works. The capture tool launches but the interface either stays in station mode or enters mode 0 - where there is no connection, but still not able to be a monitor radio. This is the primary regression affecting third-party wireless tools. Issue 2: setWLANChannel reports success but the radio only retunes once As a workaround for Issue 1, we use the built-in Wireless Diagnostics → Sniffer tool to establish monitor mode (which works fairly reliably on this hardware). Once the interface is in monitor mode via that path, we attempt to change the channel using setWLANChannel: let iface = CWWiFiClient.shared().interface(withName: "en0")! let target = iface.supportedWLANChannels()! .first { $0.channelNumber == 6 && $0.channelWidth == .width20MHz }! try iface.setWLANChannel(target) The first call succeeds (eg: channel 48 -> 6) the radio actually tunes to the requested channel and Wireshark captures frames there. Any subsequent call (eg: channel 48 -> 6 -> 1) shows the same apparent success - no error thrown, wlanChannel() updates to reflect the new channel - but the radio does not retune. Wireshark continues capturing on the first changed channel. We have tested with disassociate() and interface power cycling between attempts — neither resets the ability to retune the radio. What we have ruled out Timing: delays between calls make no difference Competing processes holding the interface wlanChannel() returning a stale cache value — it updates correctly, but diverges from actual hardware state after the first channel change Key data point: Wireless Diagnostics Sniffer works The built-in Wireless Diagnostics → Sniffer tool successfully puts the interface into monitor mode on this hardware. This confirms the card and driver are capable - the issue is that the capability is no longer reachable via CoreWLAN or via tcpdump/Wireshark's -I flag. Wireless Diagnostics Sniffer does not support live channel changes, so it cannot serve as a full workaround. The questions Is there a supported path for third-party apps to enter monitor mode on the new Wi-Fi 7 hardware on macOS 26? What is the correct mechanism for changing channels while in monitor mode - is setWLANChannel expected to retune the radio on subsequent calls, or is there a different API intended for this? The fact that Wireless Diagnostics accomplishes both (albeit, not live) confirms the hardware and driver are fully capable - we are looking for the sanctioned equivalent for third-party tools.
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363
3w
Clarification on clonefile / copyfile support of clone directories?
The man page of copyfile sates the following: COPYFILE_CLONE [..] Note also that there is no support for cloning directories" COPYFILE_CLONE_FORCE [...] Note also that there is no support for cloning directories: if a directory is provided as the source, an error will be returned. Now the man page for clonefile: > Cloning directories with these functions is strongly discouraged. Use copyfile(3) to clone directories instead. -- So am I to enumerate the content of a directory build subfolders along the way in the target destination and clone each file inside individually? If I recall NSFileManager seems to clone a large directory instantly (edit actually I remembered wrong NSFileManager does not do this. Finder seems to copy instead of clone as well). On further inspection, clonefile states that it can do this, but it is discouraged. Interesting. I wonder why. If src names a directory, the directory hierarchy is cloned as if each item was cloned individually. However, the use of clonefile(2) to clone directory hierarchies is strongly discouraged. Use copyfile(3) instead for copying directories. P.S. - Forgive me if I posting this in the wrong category, I couldn't find a "category" in the list of available categories on these forums that seems appropriate for this question.
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579
Mar ’26
Why is using clonefile for a folder strongly discouraged?
As a part of the video editing app I’m working on, I want to efficiently copy a folder of resources on the same (local) filesystem. Because iOS is on APFS, cloning (CoW) is an option. I read the documentation for clonefile(2) which states that cloning a folder works but is strongly discouraged. I did a small sample project which demonstrates that using clonefile on a folder works correctly and is 10× faster than using FileManager’s copyItem method. My questions: The main one I’m interested in: Why is using clonefile for a folder strongly discouraged? Is FileManager using cloning behind the scenes? Or more exactly how guaranteed are we it will use it? (I know it does, I tried manually cping the resources and it was thousands of times slower.)
4
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540
Mar ’26
CoreBluetooth multi-peripheral high-frequency BLE streaming shows uneven packet distribution and lag on some A16/A17 iPads
We are observing a reproducible issue on some (not all) iPad models equipped with A16, where BLE streaming from multiple peripherals at ≥33–40 Hz results in uneven packet distribution, burst delivery, and application-level lag. The same application, peripherals, firmware, iOS version, and physical environment do not exhibit this behaviour on A14-based iPads (iPad 10). Affected Hardware: • iPad 11" with A16 • iOS versions: identical across tested devices • Issue affects some devices of the same model, not all Internal field data • ~25 affected • ~5 unaffected • Customers actively prefer iPad 10 (A14) due to stability When two or more BLE peripherals stream data concurrently at frequencies ≥33–40 Hz, affected iPads exhibit: • Uneven packet arrival timing • Burst delivery instead of uniform intervals • Increasing latency over time • Observable application-level lag This does not present as simple packet loss. Instead, packets arrive in clusters, breaking real-time assumptions. At ≤30–33 Hz, the issue does not reproduce. We tested: • One affected iPad 11 • One unaffected iPad 11 • Same iOS version • Same app build • Same peripherals • Same firmware • Same physical location • Same Wi-Fi state Only the affected device reproduces the issue. This rules out: • App logic • Peripheral firmware • iOS version • Environmental RF noise • Wi-Fi coexistence configuration Evidence Available We can provide: • Screenshots from a minimal test app showing packet counts • CSV files of packet timestamps • Source code for the BLE test app • Side-by-side comparison logs (affected vs unaffected device) All evidence is from the same app, built solely to measure packet timing. Additional Technical Notes • Issue persists after factory reset • Occurs without third-party BLE libraries (CoreBluetooth only) • Occurs regardless of foreground/background state • Not correlated with MTU size • Appears threshold-based (~33–40 Hz) • Appears device-specific, not model-wide
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463
Feb ’26
New Virtualization features in macOS Tahoe
I'm pleased to share some significant updates that have recently been released for our Hypervisor and Virtualization frameworks. We've focused on enhancing efficiency, expanding capabilities, and addressing common developer needs. I believe these will be valuable for many of you. Here’s a look at what’s new: Hypervisor Updates We've introduced support for configuring the intermediate physical address (IPA) memory granularity of a VM. This allows for more granular memory mappings, enabling granularity sizes down to 4KB. This is particularly useful for certain specialized device drivers requiring finer memory control. Virtualization Framework Updates More Efficient VM Image Storage with ASIF: We've integrated support for the Apple Sparse Image Format (ASIF). This results in a smaller disk footprint and optimized transfer for VM disk images when using VZDiskImageStorageDeviceAttachment, improving storage efficiency. Custom Network Topologies with vmnet: We've added support for vmnet custom network topologies. This enables more flexible VM-to-VM communication based on logical networks with customized configurations, useful for complex testing or development environments. See VZVmnetNetworkDeviceAttachment to get started. Simplified VM Queue Discovery: It's now easier to discover a VM’s on-process thanks to a new property on VZVirtualMachine. This should aid in development and debugging when interacting directly with the VM's queue. These are some of the key highlights of the first beta, and I'm looking forward to seeing how these improvements will be utilized. I encourage you to explore the documentation for full details on these features.
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699
Jan ’26
macOS 26.1 Tahoe on ARM: FinderSync extension does not work
When running the currently latest version of macOS (26.1) on a machine with ARM CPU (I could not reproduce the issue with Intel-Based machines) Finder Sync extensions do not work any more in general. Steps to reproduce the problem: In Xcode create a new macOS App project with default settings (in my case I chose XIB for the UI and Objective-C as language, and disabled testing, but that should not make any difference) In Xcode add a new target / "Finder Sync Extension" to the project with default settings, this adds a new Finder Sync Extension with example code to the app. Run the application and open Finder and navigate to "/Users/Shared/MySyncExtension Documents" In the system settings ("Login Items & Extensions") enable the extension (Listed as "File Provider"). On systems where it is working, in the context menu of that folder an entry "Example Menu Item" will appear. On systems where it does not work it is missing. Some findings: Adding the *.appex with "pluginkit -a" registers the extension as expected, it is then visible in the system settings, removing it with "pluginkit -r" is also reflected in the system settings. "pluginkit -m -i " returns the extension on systems where it is working (assuming it is registered while this command is executed), on systems wehre it is not working, nothing is returned, regardless of the registration state. When enabling the extension in the system settings nothing more happens, there is no process started for the extension (unlike as on systems where it is working), and thus no context menu entries and no badges are displayed in Finder. Restarting Finder or the system does not help. Any ideas what I could be missing here?
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Dec ’25
How to get displayName actually used by Finder when using FileProvider API
I am developing a FileProvider extension which will be launched for one or more domains. In the case where I have two domains, say with displayNames "Foo" and "Bar", the finder will then show "MyExtension - Foo" and "MyExtension - Bar" respectively after registering them with addDomain. However, if I only have a single domain, let's say "Foo" – then I just see "MyExtension" rather than "MyExtension - Foo". Now ideally I'd like to be able to control the entire name, but barring that at least be able to show the displayName even with a single domain. How can I achieve that?
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Dec ’25
macOS26: MenuBarExtra item not showing
Hi, In macOS26 beta, our app icon is not showing anymore in the MenuBar. It is also not displayed in the new section "Menu Bar > Allow in the Menu Bar", which seems to be the way to show/hide Menu Bar icons in macOS 26. The icon is correctly displayed and working in macOS 15. Our app is signed and notarized. It also has the "LSUIElement" value set to "true" in the Info.plist file. Is there some new mandatory entitlements to add in order to have our app showing in the "Allow in the Menu Bar" section? Thanks in advance for your help. Regards
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20
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4
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806
Activity
Nov ’25
autologin required inconsistent for virtualization
Hi, I have two issues going on: Creation of macOS VMs requires autologin is enabled: Mon Apr 13 11:27:18 20 anka.log (ankahv) 511: pid 511: installing /Users/veertu/Library/Application Support/Veertu/Anka/img_lib/UniversalMac_15.6.1_24G90_Restore.ipsw... Mon Apr 13 11:27:20 40 anka.log (install) 511: (null): installation failed: Error Domain=VZErrorDomain Code=10007 "The virtual machine failed to start." UserInfo={NSLocalizedFailure=An error occurred during installation., NSLocalizedFailureReason=The virtual machine failed to start., NSUnderlyingError=0xca2c0ced0 {Error Domain=VZErrorDomain Code=-9 "The virtual machine encountered a security error." UserInfo={NSLocalizedFailure=Unable to access security information., NSLocalizedFailureReason=The virtual machine encountered a security error., NSUnderlyingError=0xca3029320 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo={NSLocalizedFailureReason=Failed to get current host key., NSUnderlyingError=0xca30292f0 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo=0xca2a88040 (not displayed)}}}}}} Mon Apr 13 11:27:20 40 anka.log (install) 511: (null): virtual machine stopped with error: Error Domain=VZErrorDomain Code=4 "Transition from state “error” to state “stopping” is invalid." UserInfo={NSLocalizedFailure=Invalid virtual machine state transition., NSLocalizedFailureReason=Transition from state “error” to state “stopping” is invalid.} Mon Apr 13 11:27:20 40 anka.log (install) 511: failed to install macOS: Error Domain=VZErrorDomain Code=10007 "The virtual machine failed to start." UserInfo={NSLocalizedFailure=An error occurred during installation., NSLocalizedFailureReason=The virtual machine failed to start., NSUnderlyingError=0xca2c0ced0 {Error Domain=VZErrorDomain Code=-9 "The virtual machine encountered a security error." UserInfo={NSLocalizedFailure=Unable to access security information., NSLocalizedFailureReason=The virtual machine encountered a security error., NSUnderlyingError=0xca3029320 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo={NSLocalizedFailureReason=Failed to get current host key., NSUnderlyingError=0xca30292f0 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo=0xca2a88040 (not displayed)}}}}}} Running a macOS 26.x VM fails for similar reasons, yet running a 15.x VM works fine: Mon Apr 13 11:20:10 20 0f5d4fe7-edac-4f6d-aebb-f185702f2c25.log (ankahv) 474: pid 474: session started on host 26.4.1 Mon Apr 13 11:20:10 40 0f5d4fe7-edac-4f6d-aebb-f185702f2c25.log (ankahv) 474: 0f5d4fe7-edac-4f6d-aebb-f185702f2c25: failed to start: Error Domain=VZErrorDomain Code=-9 "The virtual machine encountered a security error." UserInfo={NSLocalizedFailure=Unable to access security information., NSLocalizedFailureReason=The virtual machine encountered a security error., NSUnderlyingError=0x76f049e00 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo={NSLocalizedFailureReason=Failed to get current host key., NSUnderlyingError=0x76f049e60 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo={NSLocalizedFailureReason=Failed to create new HostKey., NSUnderlyingError=0x76f049dd0 {Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument" UserInfo=0x76ec49d60 (not displayed)}}}}}} Mon Apr 13 11:20:10 40 0f5d4fe7-edac-4f6d-aebb-f185702f2c25.log (ankanet) 474: failed to receive packets: Connection reset by peer This is super painful for us to manage since some of our users can't have autologin enabled (like major banks under strict MDM requirements). Or, AWS EC2 Macs which have no VNC enabled at all by default. What's the trick here to make sure we can consistently use virtualization without autologin?
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12
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3
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323
Activity
Apr ’26
macOS 26.1 – Severe lag in Open/Save panels when iCloud Drive root contains any items (FileProvider v3 regression)
I’ve filed this as FB20943098 (macOS 26.1 – FileProvider v3 synchronous enumeration bug), but posting here in case others can reproduce and add duplicates. Systems: macOS 26.1 (26B82) M4 Mac mini Pro and M4 MacBook Air Symptoms: In any app (TextEdit, Pages, Browsers, etc.), the Open/Save dialog lags for ~1s per folder navigation click. CPU spikes from fileproviderd, cloudd, bird, and siriactionsd. Key discovery: If my iCloud Drive root is empty (only “Documents” and “Downloads”), performance is perfect. As soon as any folder or file exists at the root of iCloud Drive, the lag returns immediately. Moving those items into “Documents” or “Downloads” makes everything smooth again. Analysis: Based on process traces and container paths, this appears to originate in the FileProvider.framework subsystem (via fileproviderd), which mediates iCloud Drive. Early evidence suggests that folder enumeration of the iCloud Drive container root may be blocking UI threads in macOS 26.1. I believe this may be related to the recent internal migration of the file-provider backend (often referred to as “v3”), but I do not have direct confirmation from Apple of that exact change. MacOS 26.1’s new FileProvider v3 backend seems to be blocking the Open/Save panel while enumerating the iCloud Drive root container (~/Library/Application Support/FileProvider/723EBBFF-…). Folder enumeration seems to wait synchronously for metadata from fileproviderd, and if the local SQLite DB is busy (WAL writes or sync state checks), UI freezes briefly. Workarounds: Disabling iCloud Drive entirely fixes the issue. Simply disabling Desktop/Documents sync does not help. Keeping the iCloud Drive root empty avoids the lag without turning iCloud off. I am able to store whatever I please in the Desktop or Documents folder which is currently syncing. Would appreciate if others on 26.1 could confirm. Engineers: I’ve attached fs_usage, log stream, and process samples to my Feedback ticket via the FB20943098. Expected behavior: Folder enumeration in NSOpenPanel should remain asynchronous regardless of FileProvider background activity. Open/save modal should be responsive and smooth.
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6
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1
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1.6k
Activity
Nov ’25
AccessorySetupKit documentation
This is not a question but rather a small bit of documentation on how Accessory Setup Kit actually works. I spent a couple days figuring this out so I thought let's share my findings. The example app is very light and the documentation definitely has room for improvement so here are a couple important notes. Findings: If you're running > iOS 18 and add any property to your Info.plist file you're no longer able to scan for devices by using CBCentralManager.scanForPeriphals. This will no longer return discoverable devices. Below iOS 18 these properties in the Info.plist are ignored by the OS and you can safely use the "legacy" method of connecting to bluetooth devices. If you're running > iOS 26 the removeAccessory will show a prompt to the user. If you're running < 26 you can silently remove the accessory and start each session with a clean state. If you create CBCentralManager before you start the ASK session you'll not get the state = PoweredOn. If you have 0 accessories connected to your application CBCentralManager will never enter the state = PoweredOn when you create the CBCentralManager. Pre-ASK this would be the trigger for iOS to ask the user permission. This is no longer necessary with ASK. If you have have 1 or more accessories authorized to your app this will be returned in the session.accessories after the session has started. This is an important indicator to determine app behavior. If you have 1 or more accessories CBCentralManager.scanForPeripherals will ONLY return previously authorized AND discoverable devices. Use this for when you want to connect to a previously authorized device. If you have 1 or more accessories and the CBCentralManager.scanForPeripherals returns nothing you can (safely) assume the user attempts to onboard a new device. So for my application I take the following steps: Check for iOS version, if > iOS 18 start ASK session. Are there previously authorized devices? -- yes: run CBCentralManger.scanForPeripherals -- no: show the picker Did the scan return any devices? -- yes: show UI to select device or connect with first available device in the list -- no: show the picker Feel free to add any of your findings and @Apple please update the documentation!
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2
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4
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828
Activity
Jan ’26
Bluetooth connection unexpectedly timing out with macOS Sequoia
After the macOS Sequoia update, my app seems to have an issue with Bluetooth communication between macOS and iOS that uses CoreBluetooth for Central-Peripheral communication. Setup: The iPhone (in my case: iPhone 14 Pro with iOS 18.0 (22A3354)) acts as the Central, and the Mac (in my case: 14" MacBook Pro 2023 with macOS 15.0 (24A335)) as the Peripheral. I’ve implemented a mechanism where the Central (iPhone) sends a message to the Peripheral (Mac) every 15 seconds to keep the connection alive (Because it needs to wait for notify characteristic updates). I never noticed this kind of issue before, but with macOS Sequoia I get it permanently. Issue: The connection drops unexpectedly after a period of time (sometimes 20 seconds, sometimes a few minutes) with CBErrorDomain - code 6: The connection has timed out unexpectedly. Sample Code: Peripheral (Mac): ContentView (Peripheral).txt ContentViewModel (Peripheral).txt Central (iPhone): ContentView (Central).txt ContentViewModel (Central).txt Reproduce: I attached sample code including the Central-Sample (for iPhone) and Peripheral-Sample (for Mac). Just run the Peripheral-Sample (after granting Bluetooth permissions). Then run the Central-Sample and select the Mac device in the list After selecting it should connect, discover the service & characteristic and should start writing messages to it. After some time the func centralManager(_ central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: (any Error)?) {should get called with timed out unexpectedly error. Could anyone please look into this issue and advise on whether there’s a known bug or any workaround? Any guidance would be greatly appreciated, as this impacts the stability of Bluetooth communication between the devices. Thanks in advance. Logs: I also ran the console.app during this issue which got these errors (if this is helpful): console_logs.txt
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6
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4
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3.6k
Activity
Oct ’25
Behavior of Bookmark URLs and Files App Recently Deleted – Clarification and Potential Bug
I am developing an iOS/iPadOS application and have encountered some behavior regarding Files App and security-scoped bookmarks that I would like to clarify. Additionally, I would like to report some behavior which might include a potential issue. Question1: Accessing deleted files via bookmark (Specification clarification) Our app saves file URLs as bookmarks, which file that user has selected on Files App or app-created so to open a file which user has modified previously in the next launch. When a user deletes a file in Files App (moves a file to Recently Deleted), the app can still resolve the bookmark and access the file for read/write operations. Is this behavior intended? In other words, is it correct that a bookmark can access a file that has been deleted in Files App but not permanently removed? Question2: Overwriting a file in Recently Deleted (Potential bug) We noticed that overwriting a file in Recently Deleted behaves differently depending on the method used. Current implementation 1.Create a temporary file in the same directory 2.Write content to the temporary file 3.Delete the original file ([NSFileManager removeItemAtURL:error:]) 4.Move the temporary file to the original file path ([NSFileManager moveItemAtURL:toURL:error:]) Result: The file disappears from Files App Recently Deleted. In contrast, using [NSFileManager replaceItemAtURL:withItemAtURL:] keeps the file visible in Recently Deleted. Is this difference designed behavior? If not, this may be a bug. Question3: Detecting files in Recently Deleted We want to detect whether a file resides in Recently Deleted, but we cannot find a reliable and officially supported method. Recently Deleted files appear under .Trash, but using the path alone is not a reliable method. We have tried the following APIs without success: [NSURL getResourceValue:forKey:NSURLIsHiddenKey error:] [NSURL checkResourceIsReachableAndReturnError:] [NSFileManager fileExistsAtPath:] [NSFileManager isReadableFileAtPath:] [NSFileManager getRelationship:ofDirectory:NSTrashDirectory inDomain:NSUserDomainMask toItemAtURL:error:] We could not obtain the Recently Deleted folder URL using standard APIs. [NSFileManager URLsForDirectory:NSTrashDirectory inDomains:NSUserDomainMask] [NSFileManager URLForDirectory:NSTrashDirectory inDomain:NSUserDomainMask appropriateForURL:url create:error:] Could you advise a safe and supported way to detect Recently Deleted files properly by the app?
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6
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0
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398
Activity
Mar ’26
My app seems to cause Time Machine errors
I've written an PDF viewing app, and there seems to be a correlation between files opened by the app and files that Time Machine says couldn't be backed up. The files can still "not be backed up", even after the app has closed them. Is there anything I specifically need to do to sever the link between the file and the app?
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14
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0
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357
Activity
Feb ’26
iOS App Crashes after install but not when running from Xcode
I have an odd issue I'm trying to troubleshoot. I have an app that is deployed to our enterprise and works on almost all of our devices. Lately, I have devices (very small number) where the app installs from our MDM and it crashes upon launch, it does not get past the launch screen. If I remove and reinstall the app from the MDM it still crashes. I decided to put the devices in developer mode and if I run the App from Xcode on the device it works fine. If I stop it and run it right from the device it also works. If I do a final build of the app and install it using "Devices and Simulators", the app crashes upon launch. Using "Devices and Simulators" I check for crash log for the app and no file. I am stumped as to whats going on.
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7
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0
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252
Activity
Oct ’25
Feature Proposal: CrossRun
Hi everyone! I've considered this — what if Apple added a native system-wide feature in all of iOS, iPadOS, and macOS called “CrossRun” where you can natively execute non-App Store software like Windows or Linux apps natively on your device? But not in a sluggish emulator—this would use intelligent Apple-signed Just-In-Time (JIT) compilation inside the virtual containers, and the experience would actually perform fast and feel natural. This is my vision for CrossRun: Every developer, student, creative professional, and enterprise user who relies on specialized software—whether it’s legacy Windows tools, Linux-only applications, or vintage DOS and Classic Mac utilities—feels the pain of platform lock‑in. Artists can’t run niche Linux‑based graphics programs on their iPads. Engineers can’t test x64‑only binaries on Apple Silicon without juggling emulators. Retro‑gaming fans miss their favorite DOS titles. Even enterprises struggle to standardize on Apple hardware because critical Windows‑only applications won’t run seamlessly. If we don’t push for CrossRun now, the Apple ecosystem remains siloed: iPads and iPhones will continue limited to App Store apps, Macs will still need multiple third‑party VM tools, and countless workflows stay fragmented across devices. That means slower development cycles, extra licensing costs for virtualization software, and lost opportunities for education, creativity, and business efficiency. Without CrossRun’s universal runtime, we’ll still be rebooting into different environments or paying for separate virtualization apps—year after year. Apple already provides the building blocks: Rosetta 2, Virtualization.framework, Apple Silicon—and QEMU thrives as open‑source, battle‑tested code. With the next wave of Apple Silicon devices on the horizon, demand for cross‑architecture support, legacy‑app compatibility, and enterprise containerization is only growing. Delaying another year will cost developers, businesses, and users real time and money. Let’s show Apple that the community is ready for a truly universal, system‑integrated solution—right now. Key features we should demand in CrossRun: Built‑in Apple‑signed QEMU for all ISAs (x86, ARM, RISC‑V, PowerPC, 68k, MIPS, etc.) Rosetta 2 JIT for seamless macOS and Windows x64 support Metal‑backed 3D GPU passthrough and Vulkan→Metal / Direct3D→Metal translation Downloadable OS and app containers via the App Store or verified repositories (Ubuntu, Windows ARM/x64, Android, Haiku, ReactOS, FreeBSD, retro OSes) Predictive ML pre‑warm cache to speed cold starts Dynamic resource scaling (CPU, GPU, RAM) per container iCloud‑synced snapshots and shareable VM links for cross‑device continuity Customizable on‑screen controls (D‑pad, virtual buttons, trackpad, keyboard) on iPhone, iPad, and macOS Secure sandboxing via Virtualization.framework with VM disk encryption and MDM policy enforcement Virtual LAN and VPN passthrough for container networking Developer tooling (crossrunctl CLI, Xcode debugger integration, CI/CD support) Plugin ecosystem and container SDK for community‑published templates and translation layers Let Apple know it’s time to bake CrossRun into the system and unlock a universal runtime for every app, past and future, across iOS, iPadOS, and macOS.
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1
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273
Activity
Jul ’25
KDK for current stable version (26.1) missing
The current stable macOS version, 26.1 (build 25B78) is missing a corresponding Kernel Debug Kit (KDK) on the developer downloads page. This means I can't do any kernel-level development tasks currently. For example, if I try to build a new kernel collection with kmutil I get the message Missing Developer Kit: As of macOS 13.0, you will need to install a KDK matching your build 25B78 to rebuild kernel collections. but there is no build 25B78 KDK available to download. The latest 26.1 KDK on the download page is 25B5062e (from a beta I believe) and the final stable KDK for build 25B78 (which kernel development tools require) was never published. Is there any workaround for this to correctly do kernel-level development targeting the latest stable release, or a timeline for when the KDK will release? Thanks!
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0
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3
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522
Activity
Nov ’25
CBCentralManager State Changes to PoweredOff After Using ASK for Accessory Setup
We are observing some unexpected behavior in our app when using ASK. Our app is able to successfully discover and set up an accessory via ASK. After the setup completes, the connection to the accessory is managed through CBCentralManager and works as expected. However, when we attempt to discover another accessory afterward, the picker is shown and indicates that accessory discovery is in progress. After approximately 10 seconds, the CBCentralManager delegate reports the Bluetooth state as poweredOff. Once this happens, the state never transitions back to poweredOn. At this point, the only way to reconnect to the device or continue discovery is to relaunch the app. We are wondering if anyone else has encountered similar behavior, or if this is a known or documented limitation/behavior when using ASK in combination with CBCentralManager.
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5
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3
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770
Activity
Feb ’26
Timed-Wait for main thread
The scenario is, in a macOS app (primarly), main thread needs to wait for some time for a certain 'event'. When that event occurs, the main thread is signaled, it gets unblocked and moves on. An example is, during shutdown, a special thread known as shutdown thread waits for all other worker threads to return (thread join operation). When all threads have returned, the shutdown thread signals the main thread, which was waiting on a timer, to continue with the shutdown flow. If shutdown thread signals the main thread before the later's timer expires, it means all threads have returned. If main thread's timer expires first, it means some threads have failed to join (probably stuck in infinite loop due to bug, disk I/O etc.). This post is to understand how main thread can wait for some time for the shutdown thread. There are two ways: a) dispatch_semaphore_t b) pthread conditional variable (pthread_cond_t) and mutex (pthread_mutex_t). Expanding a bit on option (b) using conditional variable and mutex: // This method is invoked on the main thread bool ConditionSignal::TimedWait() noexcept { struct timespec ts; pthread_mutex_t * mutex = (pthread_mutex_t *) (&vPosix.vMutexStorage[0]); pthread_cond_t * cond = (pthread_cond_t *) (&vPosix.vCondVarStorage[0]); // Set the timer to 3 sec. clock_gettime(CLOCK_REALTIME, &ts); ts.tv_sec += 3; pthread_mutex_lock(mutex); LOG("Main thread has acquired the mutex and is waiting!"); int wait_result = pthread_cond_timedwait(cond, mutex, &ts); switch (wait_result) { case 0: LOG("Main thread signaled!"); return true; case ETIMEDOUT: LOG("Main thread's timer expired!"); return false; default: LOG("Error: Unexpected return value from pthread_cond_timedwait: " + std::to_string(wait_result)); break; } return false; } // This method is invoked on shutdown thread after all worker threads have returned. void ConditionSignal::Raise() noexcept { pthread_mutex_t * mutex = (pthread_mutex_t *) (&vPosix.vMutexStorage); pthread_cond_t * cond = (pthread_cond_t *) (&vPosix.vCondVarStorage); pthread_mutex_lock(mutex); LOG("[Shutdown thread]: Signalling main thread..."); pthread_cond_signal(cond); pthread_mutex_unlock(mutex); } Both options allow the main thread to wait for some time (for shutdown thread) and continue execution. However, when using dispatch_semaphore_t, I get the following warning: Thread Performance Checker: Thread running at User-interactive quality-of-service class waiting on a lower QoS thread running at Default quality-of-service class. Investigate ways to avoid priority inversions Whereas, with conditional variables, there are no warnings. I understand the warning - holding the main thread can prevent it from responding to user events, thus causing the app to freeze. And in iOS, the process is killed if main thread takes more than 5 secs to return from applicationWillTerminate(_:) delegate method. But in this scenario, the main thread is on a timed-wait, for some milliseconds i.e., it is guaranteed to not get blocked indefinitely. While this is described for macOS, this functionality is required for all Apple OSes. What is the recommend way?
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3
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155
Activity
Feb ’26
How to mount custom FSKit-based file system in Finder?
Hi, I'm working with the new FSKit framework and have successfully implemented a custom file system using FSUnaryFileSystem. Mounting the file system via Terminal works perfectly — I can create, delete, and browse files and directories as expected. Since /Volumes is protected on modern macOS systems, I cannot mount my file system there directly. Instead, I mount it into a different writable directory (e.g., /tmp/MyFS) and then create a symbolic link to it in a user-visible location such as ~/Downloads/MyFS. Finder does see the symlink and displays it with a "Volume" icon, but clicking it results in an error — it cannot be opened. It seems like Finder does not treat the symlinked mount as a fully functional volume. Is there a proper way to register or announce a FSKit-mounted file system so that Finder lists it as a real volume and allows access to it? Are there additional steps (APIs, notifications, entitlements, or Info.plist keys) required to integrate with Finder? Any insight would be greatly appreciated. Thanks!
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4
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3
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397
Activity
Jun ’25
Monitor mode capture broken with Wi-Fi 7 (M5 Pro MacBook Pro) on macOS 26 - worked previously on same OS with older hardware
Platform: macOS 26.3.1, M5 Pro MacBook Pro Framework: CoreWLAN Affected applications: NetViews, Air Tool 2, and our own tooling — appears to be specific to the new Wi-Fi 7 hardware Hardware Card Type: chip id: 0x11 api 1.2 firmware [Rev 72.11.260 N1B1 devFused=0] phy [17.1.17.0], core80211 [324.10.260 N1_silicon_b] Firmware: Jan 27 2026 21:18:32 version XBS_BUILD_TAG GIT_DESCRIBE FWID chip id: 0x11 api 1.2 firmware [Rev 72.11.260 N1B1 devFused=0] phy [17.1.17.0], core80211 [324.10.260 N1_silicon_b] Driver: IO80211_driverkit-1540.16 "IO80211_driverkit-1540.16" Jan 27 2026 Background Both issues described below were working correctly on macOS 26 with previous-generation hardware. The regression is specific to the Wi-Fi 7 card shipping in the M5 Pro MacBook Pro. This is not an OS regression — it is a hardware/driver/firmware compatibility issue with the new card under macOS 26. Issue 1: disassociate() + tcpdump/Wireshark -I no longer enters monitor mode Previously, the standard approach of calling disassociate() and then launching tcpdump -i en0 -I or Wireshark -i en0 -I -k would successfully put the interface into monitor mode. On the M5 Pro Wi-Fi 7 card, this no longer works. The capture tool launches but the interface either stays in station mode or enters mode 0 - where there is no connection, but still not able to be a monitor radio. This is the primary regression affecting third-party wireless tools. Issue 2: setWLANChannel reports success but the radio only retunes once As a workaround for Issue 1, we use the built-in Wireless Diagnostics → Sniffer tool to establish monitor mode (which works fairly reliably on this hardware). Once the interface is in monitor mode via that path, we attempt to change the channel using setWLANChannel: let iface = CWWiFiClient.shared().interface(withName: "en0")! let target = iface.supportedWLANChannels()! .first { $0.channelNumber == 6 && $0.channelWidth == .width20MHz }! try iface.setWLANChannel(target) The first call succeeds (eg: channel 48 -> 6) the radio actually tunes to the requested channel and Wireshark captures frames there. Any subsequent call (eg: channel 48 -> 6 -> 1) shows the same apparent success - no error thrown, wlanChannel() updates to reflect the new channel - but the radio does not retune. Wireshark continues capturing on the first changed channel. We have tested with disassociate() and interface power cycling between attempts — neither resets the ability to retune the radio. What we have ruled out Timing: delays between calls make no difference Competing processes holding the interface wlanChannel() returning a stale cache value — it updates correctly, but diverges from actual hardware state after the first channel change Key data point: Wireless Diagnostics Sniffer works The built-in Wireless Diagnostics → Sniffer tool successfully puts the interface into monitor mode on this hardware. This confirms the card and driver are capable - the issue is that the capability is no longer reachable via CoreWLAN or via tcpdump/Wireshark's -I flag. Wireless Diagnostics Sniffer does not support live channel changes, so it cannot serve as a full workaround. The questions Is there a supported path for third-party apps to enter monitor mode on the new Wi-Fi 7 hardware on macOS 26? What is the correct mechanism for changing channels while in monitor mode - is setWLANChannel expected to retune the radio on subsequent calls, or is there a different API intended for this? The fact that Wireless Diagnostics accomplishes both (albeit, not live) confirms the hardware and driver are fully capable - we are looking for the sanctioned equivalent for third-party tools.
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363
Activity
3w
Clarification on clonefile / copyfile support of clone directories?
The man page of copyfile sates the following: COPYFILE_CLONE [..] Note also that there is no support for cloning directories" COPYFILE_CLONE_FORCE [...] Note also that there is no support for cloning directories: if a directory is provided as the source, an error will be returned. Now the man page for clonefile: > Cloning directories with these functions is strongly discouraged. Use copyfile(3) to clone directories instead. -- So am I to enumerate the content of a directory build subfolders along the way in the target destination and clone each file inside individually? If I recall NSFileManager seems to clone a large directory instantly (edit actually I remembered wrong NSFileManager does not do this. Finder seems to copy instead of clone as well). On further inspection, clonefile states that it can do this, but it is discouraged. Interesting. I wonder why. If src names a directory, the directory hierarchy is cloned as if each item was cloned individually. However, the use of clonefile(2) to clone directory hierarchies is strongly discouraged. Use copyfile(3) instead for copying directories. P.S. - Forgive me if I posting this in the wrong category, I couldn't find a "category" in the list of available categories on these forums that seems appropriate for this question.
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5
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579
Activity
Mar ’26
Why is using clonefile for a folder strongly discouraged?
As a part of the video editing app I’m working on, I want to efficiently copy a folder of resources on the same (local) filesystem. Because iOS is on APFS, cloning (CoW) is an option. I read the documentation for clonefile(2) which states that cloning a folder works but is strongly discouraged. I did a small sample project which demonstrates that using clonefile on a folder works correctly and is 10× faster than using FileManager’s copyItem method. My questions: The main one I’m interested in: Why is using clonefile for a folder strongly discouraged? Is FileManager using cloning behind the scenes? Or more exactly how guaranteed are we it will use it? (I know it does, I tried manually cping the resources and it was thousands of times slower.)
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540
Activity
Mar ’26
CoreBluetooth multi-peripheral high-frequency BLE streaming shows uneven packet distribution and lag on some A16/A17 iPads
We are observing a reproducible issue on some (not all) iPad models equipped with A16, where BLE streaming from multiple peripherals at ≥33–40 Hz results in uneven packet distribution, burst delivery, and application-level lag. The same application, peripherals, firmware, iOS version, and physical environment do not exhibit this behaviour on A14-based iPads (iPad 10). Affected Hardware: • iPad 11" with A16 • iOS versions: identical across tested devices • Issue affects some devices of the same model, not all Internal field data • ~25 affected • ~5 unaffected • Customers actively prefer iPad 10 (A14) due to stability When two or more BLE peripherals stream data concurrently at frequencies ≥33–40 Hz, affected iPads exhibit: • Uneven packet arrival timing • Burst delivery instead of uniform intervals • Increasing latency over time • Observable application-level lag This does not present as simple packet loss. Instead, packets arrive in clusters, breaking real-time assumptions. At ≤30–33 Hz, the issue does not reproduce. We tested: • One affected iPad 11 • One unaffected iPad 11 • Same iOS version • Same app build • Same peripherals • Same firmware • Same physical location • Same Wi-Fi state Only the affected device reproduces the issue. This rules out: • App logic • Peripheral firmware • iOS version • Environmental RF noise • Wi-Fi coexistence configuration Evidence Available We can provide: • Screenshots from a minimal test app showing packet counts • CSV files of packet timestamps • Source code for the BLE test app • Side-by-side comparison logs (affected vs unaffected device) All evidence is from the same app, built solely to measure packet timing. Additional Technical Notes • Issue persists after factory reset • Occurs without third-party BLE libraries (CoreBluetooth only) • Occurs regardless of foreground/background state • Not correlated with MTU size • Appears threshold-based (~33–40 Hz) • Appears device-specific, not model-wide
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3
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463
Activity
Feb ’26
New Virtualization features in macOS Tahoe
I'm pleased to share some significant updates that have recently been released for our Hypervisor and Virtualization frameworks. We've focused on enhancing efficiency, expanding capabilities, and addressing common developer needs. I believe these will be valuable for many of you. Here’s a look at what’s new: Hypervisor Updates We've introduced support for configuring the intermediate physical address (IPA) memory granularity of a VM. This allows for more granular memory mappings, enabling granularity sizes down to 4KB. This is particularly useful for certain specialized device drivers requiring finer memory control. Virtualization Framework Updates More Efficient VM Image Storage with ASIF: We've integrated support for the Apple Sparse Image Format (ASIF). This results in a smaller disk footprint and optimized transfer for VM disk images when using VZDiskImageStorageDeviceAttachment, improving storage efficiency. Custom Network Topologies with vmnet: We've added support for vmnet custom network topologies. This enables more flexible VM-to-VM communication based on logical networks with customized configurations, useful for complex testing or development environments. See VZVmnetNetworkDeviceAttachment to get started. Simplified VM Queue Discovery: It's now easier to discover a VM’s on-process thanks to a new property on VZVirtualMachine. This should aid in development and debugging when interacting directly with the VM's queue. These are some of the key highlights of the first beta, and I'm looking forward to seeing how these improvements will be utilized. I encourage you to explore the documentation for full details on these features.
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699
Activity
Jan ’26
macOS 26.1 Tahoe on ARM: FinderSync extension does not work
When running the currently latest version of macOS (26.1) on a machine with ARM CPU (I could not reproduce the issue with Intel-Based machines) Finder Sync extensions do not work any more in general. Steps to reproduce the problem: In Xcode create a new macOS App project with default settings (in my case I chose XIB for the UI and Objective-C as language, and disabled testing, but that should not make any difference) In Xcode add a new target / "Finder Sync Extension" to the project with default settings, this adds a new Finder Sync Extension with example code to the app. Run the application and open Finder and navigate to "/Users/Shared/MySyncExtension Documents" In the system settings ("Login Items & Extensions") enable the extension (Listed as "File Provider"). On systems where it is working, in the context menu of that folder an entry "Example Menu Item" will appear. On systems where it does not work it is missing. Some findings: Adding the *.appex with "pluginkit -a" registers the extension as expected, it is then visible in the system settings, removing it with "pluginkit -r" is also reflected in the system settings. "pluginkit -m -i " returns the extension on systems where it is working (assuming it is registered while this command is executed), on systems wehre it is not working, nothing is returned, regardless of the registration state. When enabling the extension in the system settings nothing more happens, there is no process started for the extension (unlike as on systems where it is working), and thus no context menu entries and no badges are displayed in Finder. Restarting Finder or the system does not help. Any ideas what I could be missing here?
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10
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533
Activity
Dec ’25
How to get displayName actually used by Finder when using FileProvider API
I am developing a FileProvider extension which will be launched for one or more domains. In the case where I have two domains, say with displayNames "Foo" and "Bar", the finder will then show "MyExtension - Foo" and "MyExtension - Bar" respectively after registering them with addDomain. However, if I only have a single domain, let's say "Foo" – then I just see "MyExtension" rather than "MyExtension - Foo". Now ideally I'd like to be able to control the entire name, but barring that at least be able to show the displayName even with a single domain. How can I achieve that?
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2
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623
Activity
Dec ’25