Some Macs recently received a macOS system update which disabled the simulator runtimes used by Xcode 15, including the simulators for iOS, tvOS, watchOS, and visionOS. If your Mac received this update, you will receive the following error message and will be unable to use the simulator:
The com.apple.CoreSimulator.SimRuntime.iOS-17-2 simulator runtime is not available.
Domain: com.apple.CoreSimulator.SimError
Code: 401
Failure Reason: runtime profile not found using "System" match policy
Recovery Suggestion: Download the com.apple.CoreSimulator.SimRuntime.iOS-17-2 simulator runtime from the Xcode
To resume using the simulator, please reboot your Mac. After rebooting, check Xcode Preferences → Platforms to ensure that the simulator runtime you would like to use is still installed. If it is missing, use the Get button to download it again.
The Xcode 15.3 Release Notes are also updated with this information.
Simulator
RSS for tagRapidly prototype and test builds of your app during the development process using Simulator.
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Hi, We are trying to use Apple Security API for KeyChain Services. The motive is to store some sensitive data in the KeyChain. Our app has Network extensions enabled which share a common app group and we want to access the data stored in the KeyChain from the extensions as well. Specifically we were exploring the SecItemAdd, SecItemCopyMatching etc family of APIs. We tried a few methods:
Using the common App Group : Specifying the common app group in the "kSecAttrAccessGroup" field of the KeyChain query, allowed us to have a shared keychains for different apps (targets) in the app group, but this did not work for extensionsEnabling the KeyChain Sharing capability : We enabled the KeyChain Sharing Ability in the extensions and the app target as well, giving a common KeyChain Access group. Specifying this in the kSecAttrAccessGroup field also did not work.We tried specifying "$AppIdentifier.KeyChainSharingGroup" in the kSecAttrAccessGroup field , but this did not work as wellThe error code which we get in all these 3 cases when trying to access the Keychain from the extension is error code 25291 (errSecNotAvailable). The Documentation says this error comes when "No Trust Results are available" and printing the error in xcode using the status says "No keychain is available. You may need to restart your computer". The online Documentation says that it is possible to share keychain with extensions, but by far we are unable to do it with the methods suggested.Do we need any special entitlement for this or is there something we are missing while using these APIs?If this is possible Is there any internal/open source wrapper for Keychain APIs, that we can use?We will really appreciate help in solving this issue!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?
Up until some point relatively recently, I have been able to use Safari's web inspector to connect to the iOS simulator in order to debug our web application in development at http://localhost:8088.
Now, the web inspector still OPENS, but it opens in a broken state. The context is available to select from Safari's "Develop" menu: Develop > "iPhone 16 Pro (Simulator)" > "localhost - login". It appears under the Safari heading if I have navigated to the web app in the browser, or under the Expo heading if I am accessing it through the webview in our React Native wrapper app. When I select it, the web inspector window does appear.
However, once it opens, the Elements pane is empty, the Console pane is empty, expressions entered into the console are not evaluated, there's no content in Sources, Network, Storage, etc.
Important notes:
This broken state happens at http://localhost:8088 as well as http://127.0.0.1:8088, and it seems that the insecure context is the issue.
The web inspector DOES work for HTTPS sites. If I navigate to, e.g., https://example.com in the simulator and connect the web inspector, everything works fine.
The web inspector also works fine in Safari on macOS (OUTSIDE the simulator) when accessing non-HTTPS sites. It's only a problem for non-HTTPS sites when connecting to the simulator.
A coworker has the same problem, so it is not isolated to my machine.
I would enable TLS locally as a workaround, but this web app is very complex, and I know from experience that it is very difficult for various reasons to set it up properly for our project in development, and it will take significant non-trivial work to do so.
So... Why is this happening? Is this expected behavior? Is there a way that I can debug my site on localhost without HTTPS?
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)
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
Topic:
Developer Tools & Services
SubTopic:
Xcode
Tags:
Xcode Previews
Xcode
Simulator
Business and Enterprise
In previous versions of the simulator, it was possible to import files into the Files app by dragging them from the Finder into the Simulator. It appears that in the iOS 26 Simulator, this opens the file in Safari.
I've only tried it with .json files so far.
The documentation at https://developer.apple.com/documentation/xcode/sharing-data-with-simulator says that the original behaviour should happen:
To add files to Simulator, select one or more files in Finder on your Mac, then click the Share button. Select Simulator from the share destination list. Choose the simulated device from the drop-down list. Simulator opens the Files app, and lets you select where to save the files.
I'd love to learn if this is intentional behaviour, and if so, what workarounds there might be. I use this pattern quite a lot, as I have a HealthKit app, and I've built a system that allows me to export workouts as JSON files from a real device, that I can then import into a simulator for testing.
Edit: I found a workaround. Make a folder in Files.app, then search for it within ~/Library/Developer/CoreSimulator/Devices. Open the folder in Finder, then add any files you want to be available in the Simulator.
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.
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
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?
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?
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
Topic:
Developer Tools & Services
SubTopic:
Xcode
Tags:
Xcode Previews
Xcode
Simulator
Business and Enterprise
We have the following step before running any tests on CI machine:
xcrun simctl shutdown all && xcrun simctl erase all
It was working perfectly before Xcode 26.1.
On Beta 3 it was doing it for 15 min every time.
When updated to RC1, the tests with cached build are fast (clean goes up to 10 sec), but the package tests clean is still going up to 15 min every time.
We did
xcrun simctl runtime dyld_shared_cache update --all
as advised but it's helping only temporarily. Is this going to be fixed in the official release?
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?
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)
Everytime when iOS simulator is launched I het a lot of repeated "*** quit unexpectedly" alerts.
Where "***" is a mix of "managedappdistributiond","healthappd", and "findmylocated"
Even after the simulator is launched I still het random "*** quit unexpectedly" alerts.
Very annoying because the alerts deactivates the active window
This is on an MacBook Pro M3 Max,, Xcode 15.2, Sonoma 14.2.1, it also happens with Xcode 15.1
A co developer (MacBook Pro M1 Max,Xcode 15.2, Sonoma 14.2.1) does not have the issue
Any idea how I can prevent this from happening?
Update
Every mentioned service crash happens in libswiftCore.dylib at
0x1929f3938 assertionFailure(:_:file:line:flags:) + 248
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.