I'm trying to download an iOS Simulator runtime in Xcode 26.2 or 26.1 on macOS 26.1, but the download keeps failing with the following error: Download failed. Domain: DVTDownloadableErrorDomain Code: 41 Failed fetching catalog for assetType (com.apple.MobileAsset.iOSSimulatorRuntime), serverParameters ({ RequestedBuild = 23C54;}) Domain: DVTDownloadsUtilitiesErrorDomain. Code: -1. Download failed due to a bad URL. (Catalog download for com.apple.MobileAsset.iOSSimulatorRuntime) Domain: com.apple.MobileAssetError.Download Code: 49 User Info: {checkConfiguration = 1;} macOS & Xcode Info: macOS Version: 26.1 (Build 25B78) Xcode Version: 26.2 (24553) (Build 17C52) What I've tried so far: Formatted my Mac and reinstalled Xcode multiple times. Completely deleted Xcode and its related files several times (/Applications/Xcode.app, caches, preferences). Tried different internet connections from multiple locations. Checked Apple servers and verified network. Attempted downloading other simulator runtimes (fail). but download fails immediately with DVTDownloadableErrorDomain Code 41 and bad URL error. Question: How can I fix the simulator download issue in Xcode 26.2 on macOS 26.1? Is there a known workaround for the bad URL / catalog download error?

Hi, I’m facing a consistent simulator boot issue that appears to start after iOS 18.2 simulator runtimes and persists in 18.6, 26.1, and 26.2. Observed behavior iOS 18.2 simulator works fine iOS 18.6 simulator does NOT boot iOS 26.1 / 26.2 simulators do NOT boot Tried everything reinstall/clear cache and all and event formatted the system Unable to boot the Simulator NSPOSIXErrorDomain Code: 4 Failure Reason: Interrupted system call Failed to start launchd_sim: could not bind to session, launchd_sim may have crashed or quit responding macOS: Sequoia Xcode: 26.1, 26.2 Machine: Apple Silicon Unable to boot the Simulator. Domain: NSPOSIXErrorDomain Code: 4 Failure Reason: Interrupted system call User Info: { DVTErrorCreationDateKey = "2025-12-26 02:19:27 +0000"; IDERunOperationFailingWorker = "_IDEInstalliP.honeSimulatorWorker", Session = "com apple CoreSimulator.SimDevice CCDECA56-4A59-491B-A830-0F3928FCD957"; } Failed to start launchd_sim: could not bind to session, launchd_sim may have crashed or quit responding Domain: com.apple.SimLaunchHostService.RequestError Code: 4 Event Metadata: com.apple. dt. DERunOperationWorkerFinished : { "device_identifier" = "CCDECAE6-4A59-491B-A830-0E3928FCD957"; "device_model" = "iPhone18, 1"; "device_osBuild" = "26.1 (23B86)"; "device_osBuild_monotonic" = 2301008600; "device_os_variant" = 1; "device_platform" = "com apple.platform.iohonesimulator"; "device_platform_family" = 2; "device_reality" = 2; "device_thinningType" = "iPhone18,1"; "device_transport" = 4; "launchSession_schemeCommand" = Run; "launchSession_schemeCommand_enum" = 1; "launchSession_targetArch" = arm64; "launchSession_targetArch_enum" = 6; "operation_duration_ms" = 1183; "operation_errorCode" = 4; "operation_errorDomain" = NSPOSIXErrorDomain; "operation_errorWorker" = "_IDEInstalliPhoneSimulatorWorker"; "operation_error_reportable" = 1; "operation_name" = IDERunOperationWorkerGroup; "param_consoleMode" = 1; "param_debugger_attachToExtensions" = 0; "param_debugger_attachToXPC" = 1; "param_debugger_type" = 3; "param_destination_isProxy" = 0; "param_destination_platform" = "com apple platform Please help on this as it got stuck. Thanks

Hello, I was wondering what simulator device is the Xcode Playground tested on? Is it better to support all screen sizes (e.g. IPads, IPhones..etc) and different orientations? Thanks!

There are multiple iOS simulator runtimes located at /System/Library/AssetsV2/com_apple_MobileAsset_iOSSimulatorRuntime which I don't need. I tried the following approaches to delete them but not working. Xcode > Settings > Components > Delete (It can delete some but not all of them) xcrun simctl runtime list (It doesn't show the old runtimes) sudo rm (Operation not permitted) sudo rm -rf cc1f035290d244fca4f74d9d243fcd02d2876c27.asset Password: rm: cc1f035290d244fca4f74d9d243fcd02d2876c27.asset/AssetData/096-69246-684.dmg: Operation not permitted rm: cc1f035290d244fca4f74d9d243fcd02d2876c27.asset/AssetData: Operation not permitted rm: cc1f035290d244fca4f74d9d243fcd02d2876c27.asset/Info.plist: Operation not permitted rm: cc1f035290d244fca4f74d9d243fcd02d2876c27.asset/version.plist: Operation not permitted rm: cc1f035290d244fca4f74d9d243fcd02d2876c27.asset: Operation not permitted I have two questions: Why "xcrun simctl runtime list" is unable to list some old runtimes? How to delete them?

Hello, I have a question about running tests on multiple simulators. Currently, my company has a WDIO+Appium test suite with XCUITEST driver that runs on a single simulator through a mockttp proxy (we are intercepting and mocking some of the responses from our APIs and pass through the rest). In order to route the traffic we are currently using 'networksetup -setsecurewebproxy '. Everything works as expected. With growing number of tests we'd like to scale number of simulators on a single host to 3-5. We have a working setup but the problem are system-wide proxy settings routing traffic from multiple simulators, which we can't distinguish by UDID or any other means, we know of. We can spin multiple mock servers on the same machine but we are struggling to find the way to route the traffic on a simulator basis. In the end, both options are viable: 1 mock server running for multiple simulators N number of mock servers for N number of simulators Has anyone had the same/similar problem? How to approach this? We are currently running on Sequoia OSX and platform version 18.6. Thanks!

Currently Xcode has iOS simulators that allow easily testing apps on older versions of iOS. It would be helpful if there was also a macOS simulator for testing apps on older versions of macOS. FB21229682 https://github.com/feedback-assistant/reports/issues/724

This is a M4 iMac 32GB 2TB where over the last few months memory use has been crazy. The worst offender is SimulatorTrampoline. I just opened a default iOS app and ran it in a simulator. So this is as simple as it gets: there's 1 SF Symbol and "Hello, world!" text. iStatMenus shows SimulatorTrampoline at 10.7GB, Safari 5.2GB, Xcode at 3.2GB, and swap at 548MB meanwhile ActivityMonitor shows the top memory use of Ildb-rpc-server at 2.30GB, Xcode at 523.4MB Swap is 548MB is the only number that matches and the fact that Memory used is ~26GB total. Is this amount of memory use normal? Is iStat menu reporting something different than Activity monitor. This computer used to never swap. Any suggestions?

Hi everyone, I’m experiencing a persistent issue when trying to download the iOS Simulator Runtime 26.1 on Xcode (version 26.1). The download always fails with the following error Download failed due to a bad URL. (Catalog download for com.apple.MobileAsset.iOSSimulatorRuntime) Domain: com.apple.MobileAssetError.Download Code: 49 I’m located in Brazil, so I initially thought it might be region-related, but I’ve already tried several attempts to fix it, including: Using VPNs for the US and Europe Installing the Xcode 26.2 beta Downgrading Xcode to earlier versions Reinstalling the same version of Xcode Restarting Xcode and my Mac Switching networks Clearing simulator support/device files Unfortunately, nothing has resolved the issue. Is anyone else facing this problem? Does anyone know a workaround or a manual way to download/install the iOS 26.1 simulator runtime? Thanks in advance!

I have a small, simple iOS project that doesn't use a lot of memory or libraries or anything. If I open my iOS project in XCode and run it on the iPhone 17 simulator, my memory consumption (as seen in Activity Monitor) goes into the yellow zone. Granted, I have some other apps open (Safari, Mail, Messages, the usual stuff that people run) but nothing especially demanding. Without XCode and the Simulator running, my memory consumption is only around 25% on the Activity Monitor graph. Is this expected behavior with Tahoe and iOS 26? I was able to work on my project without running out of RAM on this same computer for the past 4 years no problem. Now it seems I have a problem.

CRITICAL: iOS 26.1 Simulator Runtime (Build 23B86) Missing / MobileAsset Catalog Failing Summary After updating macOS and Xcode, I can no longer download or install the required iOS 26.1 simulator runtime. The Xcode Components system fails for all assets, and the MobileAsset catalog for iOS simulator runtimes appears to be missing or invalid. The runtime is also not listed on developer.apple.com. This issue blocks me from running any iOS simulators. Steps to Reproduce Update to: macOS 26.1 (25B78) Xcode 26.1.1 (24455 / 17B100) Open Xcode → Settings → Platforms/Components Attempt to download: iOS 26.1 Simulator Runtime Any other downloadable component (e.g., Predictive Code Completion Model) Alternatively, try using: xcodebuild -downloadPlatform iOS -exportPath ~/Downloads xcodebuild -downloadPlatform iOS -buildVersion 26 Observed Behaviour Xcode Components Downloads Fail Attempting to download the iOS 26.1 runtime results in: Download failed. Domain: DVTDownloadableErrorDomain Code: 41 Additional detail: Failed fetching catalog for assetType (com.apple.MobileAsset.iOSSimulatorRuntime) Domain: DVTDownloadsUtilitiesErrorDomain Code: -1 And: Download failed due to a bad URL. Domain: com.apple.MobileAssetError.Download Code: 49 User Info: { checkConfiguration = 1 } Predictive Code Completion Model Also Fails The operation couldn’t be completed. (IDELanguageModelKit.IDEModelDownloadAdapter.DownloadError error 2.) Domain: IDELanguageModelKit.IDEModelDownloadAdapter.DownloadError Code: 2 There was an error transferring over the network. Code: 2 CLI Downloads Fail Command: xcodebuild -downloadPlatform iOS -exportPath ~/Downloads Result: DVTDownloadable: Download Failed … iOS 26.1 Simulator (23B86) Command: xcodebuild -downloadPlatform iOS -exportPath ~/Downloads -buildVersion 26 Result: iOS 26 is not available for download. Runtime Not Listed on Developer Downloads The following page does not list iOS 26.1 simulator runtime: https://developer.apple.com/download/all/ Expected Behaviour Xcode should be able to fetch the MobileAsset catalog and download iOS 26.1 simulator runtime. The runtime should appear in the Components tab and on developer.apple.com/download/all/. CLI tools should successfully download the platform. System Information macOS: 26.1 (Build 25B78) Xcode: 26.1.1 (24455) (Build 17B100) Timestamp: 2025-11-17 Impact This issue currently prevents: Running any iOS simulator Testing or building on the required runtime Using other Xcode downloadable components (language models, etc.) This is a blocking issue for development. Notes Multiple Xcode reinstallations attempted macOS restarts performed Network connectivity normal Issue persists across all download methods (GUI + CLI)

Out of nowhere I got some red banner on top of my iPhone 13 mini / iOS 17.5. I cannot pin point the root cause of this. What I can say is that it only happens to Simulators of a certain type, e.g. iPhone 12 and 13 mini, but not iPhone 14 for example. I have installed Xcode 26.1.0 and 26.1.1, out of which 26.1.0 is selected: $ xcode-select -p /Applications/Xcode-26.1.0.app/Contents/Developer And following runtimes: $ xcrun simctl runtime list == Disk Images == -- iOS -- iOS 17.5 (21F79) - CF933623-A258-44F8-B248-C0F25C0C343B (Ready) iOS 26.1 (23B80) - D11C3CDC-EE3D-44CC-8B92-9B7D00B54B0B (Ready) Total Disk Images: 2 (14.6G) Installing the newer 26.1 23B86 runtime doesn't help either.

I'm attempting to install a previously downloaded .xcappdata to my running application on the iPadOS Simulator (running iPadOS 26.1), but the app data won't transfer to the simulator. I've created the Xcode basic iPadOS app template, without any code modifications - adding some items to the list and downloading the .xcappdata from an attached iPad (running iPadOS 26.1). I can remove the app from the iPad and re-attach the .xcappdata to the physical iPad - no issues there. The issues I'm having is when trying to attach the app data on a simulator. Steps I've tried: Manually drag and dropping the .xcappdata file to the simulator. I get a popup saying "Simulator device failed to install application data container." Attaching the .xcappdata through Xcode in the "Edit Schemes"->Options->App Data App starts fresh without any errors or items from the .xcappdata file Installing the .xcappdata file through the command line through xcrun simctl install_app_data <SIM_DEVICE_ID> <MY_XCAPPDATA> This gives an error: Simulator device failed to install application data container. Could not get the existing data container location for the app. Container manager error code: 55 Underlying error (domain=com.apple.containermanager, code=55): Failed to install the requested app data package Could not get the existing data container location for the app. Container manager error code: 55 I can however reach the "data container location" through the xcrun simctl get_app_container command, leading me to think there are some issues with underlying permissions?

Hello, I am facing a recurring issue with Xcode iOS simulator (preview). I want to preview a SwiftUI for iOS in Xcode, but the Simulator app fails to boot up. I receive the following error in Xcode: Cannot Preview in this file. Simulator was shutdown during an update. I have tried the following: Completely uninstalling XCode and deleting all developer data, then reinstalling everthing again. Shutdown and restart Deleting all developer data, deleting XCode cache Reinstalling iOS Simulator runtimes and reconfiguration of simulators. Tested using different simulator and runtime versions. "xcrun simctl --set previews delete al" My reported issues: FB20987522 FB20485454 Thank you Best regards, Jens

Hello, I am facing a recurring issue with Xcode iOS simulator (preview). I want to preview a SwiftUI for iOS in Xcode, but the Simulator app fails to boot up. I receive the follow error in Xcode: Cannot Preview in this file. Simulator was shutdown during an update. I have tried the following: Uninstall Xcode and reinstall it again Deleting all developer data Deleting Xcode cache Reinstalling iOS Simulator runtimes and reconfiguration of simulators. Tested using different simulator and runtime versions. "xcrun simctl --set previews delete al" I reported the issue: FB20485454 FB20987522 Thank you. Best regards, Jens

Since iOS 26.1 the AlarmKit alerts don't work anymore on simulator when the screen is locked. This is also still broken on the current Xcode 26.2 beta. They do trigger on the home screen and in-app though. Also on device everything works fine. Is there any secret trick to make it work again?

Simply opening Simulator app (26.0) causes high CPU usage on macOS Tahoe (26.1). ReportCrash process usage is very high throughout and causes the system to heat up pretty soon. Looking into Console app for the logs found MercuryPosterExtension process is keep on crashing. (Check under Crash Reports) simctl Diagnose https://download.developer.apple.com/OS_X/OS_X_Logs/simctl_Diagnose_Logging_Instructions.pdf Share the Simulator Diagnose report while reporting, Thanks. I have raised a ticket/feedback with Apple. I request all of you to raise one too so this gets fixed soon. Apple Feedback Assistant - FB20985249

Hello Apples, Noticed that after iOS 26.1 update the Xcode simulator seems to be prompting to login with Apple ID arbitrarily while working on some UI tests. This does not happen with previous iOS 26.0 or 26.0.1 but is now causing trouble when launching the app or uninstalling at teardown. The current other issue with the uninstallation being sticky and taking a long time (waiting for springboard to become idle) is not helping either. The dialog seems to appear a bit unreliably to be able to handle it correctly. Have tried both manual springboard dialog mapping and handling as well as an interruption monitor. The latter only seems to work for the first dialog which appears but then ceases to function so not much help… Anyone else seeing this and are there any knowledge or good workarounds? Or should we just roll back to testing with previous OS versions and cross fingers for iOS 26.2? Bottom line we cannot login with an Apple ID while running tests on a simulator… As bonus noticed the simulator background images are not working? Thanks! BR, ARu_ (Senior QE)

[Submitted as FB20950954] Xcode Simulator causes crackling and distortion in audio playback across all apps (Apple Podcasts, Music, third-party). REPRO STEPS Open any audio app and start playback Note the audio quality Launch Xcode Simulator After a few seconds, note audio quality again Quit Xcode Simulator Audio returns to normal CURRENT Audio has crackling and distortion while Simulator is running. EXPECTED Clean audio playback regardless of whether Simulator is running. SYSTEM INFO macOS 26.1 (25B78) Xcode 26.1 (17B55) Simulator 26.0 (1058)

When I use Xcode 26 (0.1, 1) for debugging and hit a breakpoint, using "step over" causes the debugger to freeze at a random line of code. Clicking "Pause program execution" indicates that the line is being executed, but the breakpoint never exits, seemingly causing a freeze. The application on the simulator also becomes unresponsive. However, when I do not use breakpoints, my program runs smoothly, and debugging on a physical device does not cause any freezes. This issue only occurs with the simulator. I am using Xcode on Apple Silicon, and due to some third-party SDKs that depend on Rosetta, our app can only run on the Rosetta simulator. We did not encounter this issue when using Xcode 16.x for simulator debugging. The current situation with Xcode 26.x significantly reduces our development efficiency. What could be causing this, and is there a solution?

My MBP M1 Pro gets really hot. iOS 26.1 Simulator in Xcode 26.1 makes ReportCrash process run at 60-160% of CPU shows Activity Monitor. MacOS 26.1. I've reported this via Feedback Assistant: FB20918609. Is there a way to quit this process permanently? When I Force Quit this it opens again immediately. Only way to stop it is to quit Simulator. But then again, I need to use the Simulator.