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.
Posts under Simulator tag
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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
I've recently updated to Xcode 26.3 and I can't download any iOS Simulator Runtime from 26.2 to 18.0, every download gives me:
Download failed.
Domain: DVTDownloadableErrorDomain
Code: 41
User Info: {
DVTErrorCreationDateKey = "2026-03-03 16:14:50 +0000";
}
--
Download failed.
Domain: DVTDownloadableErrorDomain
Code: 41
--
System Information
macOS Version 26.4 (Build 25E5218f)
Xcode 26.3 (24587) (Build 17C529)
Timestamp: 2026-03-03T17:14:50+01:00
I tried cleaning every cache, and logging in and out of my account.
I saw some reddit posts where they suggested to check out VPNs, host files and other stuff but everything was okay, also I can reach apple cdns etc.
I also tried using Xcode beta 26.4 and going back to 26.2 but still the same problem.
Anyone has a solution?
I'm building an app which runs around the Foundation model framework. My expected output is generated when testing on a real device or in preview in Xcode but it throws Foundation Model error when I try running it on the simulator. I'm using a Macbook M1 air and have apple intelligence turned on and my simulator run destination is also an iPad Pro M5 (26.0).
Any solution for this as this is my submission for the SSC so I need to make it work on the simulator iPad.
Thank you👾
Topic:
Developer Tools & Services
SubTopic:
Swift Playground
Tags:
Swift Student Challenge
Xcode
Simulator
Apple Intelligence
Have a peculiar problem I'm not able to solve. Working on an app with a mapview in the max zoomed out globe level. For some reason this morning Xcode froze/crashed when I was working and I had to force quit to get it back up. Then a new issue of graphical artifacts on the space section of the Mapview showed up.
This Tuesday has now been spent in full on trying to solve this to no avail.
I created a new project for iOS/iPadOS and added a similar map implementation. It works fine.
I used Claude to help me after a few reinstalls of Xcode with this. I asked claude to summarize - this is what has been done:
Claude generative AI summary starts here----------
Here's a complete summary of everything attempted:
The Problem
SwiftUI tvOS app with MapKit globe view showing severe rendering artifacts — corrupted pixels surrounding the globe. Started after Xcode crashed while the tvOS simulator was actively running. iOS simulator, macOS Maps app, and all native apps work perfectly. Only tvOS simulator MapKit is affected.
Hardware Confirmed Fine
Geekbench 6 Metal GPU score: 124,666 (normal for M1 Max)
Apple Diagnostics (Apple Silicon method): No issues found
macOS Maps globe renders perfectly
Everything That Was Attempted
Simulator resets:
Erased all simulator content and settings
Created brand new simulator devices
Deleted derived data
Killed CoreSimulator service
Runtime reinstalls:
Removed and reinstalled tvOS platform runtime multiple times
Tested on Xcode 26.3 and 26.4 beta — same issue on both
Installed fresh tvOS runtime after full Xcode reinstall
Cache clearing:
~/Library/Caches/com.apple.CoreSimulator
~/Library/Saved Application State/com.apple.iphonesimulator.savedState
All Metal shader caches in /private/var/folders/ including:
com.apple.CoreSimulator.SimRenderingServices.SimMetalHost
com.apple.CoreSimulator.SimRenderingServices.SimRenderServer
com.apple.CoreSimulator.CoreSimulatorService
com.apple.iphonesimulator
com.apple.dt.Xcode
com.apple.dt.xcodebuild
com.apple.CoreSimulator.simctl
~/Library/Developer/Xcode/XcodeToMetalToolchainIndexMapping.plist
~/Library/Developer/Xcode/SDKToSimulatorIndexMapping.plist
~/Library/Developer/Xcode/DerivedData
Full Xcode reinstall:
Deleted Xcode completely
Removed ~/Library/Developer
Removed all Xcode-related caches and preferences
Fresh install from Mac App Store
APFS simulator volume cleanup (required disabling SIP):
Discovered 138GB of orphaned APFS simulator volumes in /Library/Developer/CoreSimulator/Volumes/ that were protected by SIP and couldn't be deleted normally
These volumes were left in a corrupted/limbo state from the original Xcode crash
Temporarily disabled SIP via Recovery Mode
Successfully deleted all orphaned volumes
Re-enabled SIP
Reinstalled fresh tvOS runtime
Metal Toolchain:
Found three leftover Metal Toolchains (17A324, 17A5241c, 17A5295f) in Xcode settings
Cleared toolchain index mapping file
Reinstalled fresh Metal Toolchain with new tvOS runtime
Current State
Fresh Xcode installation
Fresh tvOS runtime
All simulator volumes cleared
SIP re-enabled
Issue still persists
What Has NOT Been Checked
/Library/Developer/CoreSimulator/Cryptex
/Library/Developer/CoreSimulator/Images
/Library/Developer/CoreSimulator/Profiles
Conclusion
This is almost certainly a bug triggered by the hard Xcode crash corrupting something at a level that has survived complete reinstallation of Xcode and all simulator components. The corruption is somewhere in a system-level component that normal developer tools cannot reach. Requires Apple Developer Technical Support or escalation via Feedback Assistant with the full timeline and screenshots.
For Apple's reference:
Machine: MacBook Pro M1 Max
Xcode: 26.3 / 26.4 beta (both affected)
Started: After hard Xcode crash while tvOS simulator was actively rendering MapKit globe
Affected: tvOS simulator MapKit globe only
Not affected: iOS simulator, macOS Maps, all native apps
----------(Claude generative AI summary ends here) -----------
Anyone seen this before? Absolutely wild. Can't think of more things to try.
Been eyeing a new Macbook for a while. Strange coincidence that the new M5 Macbook Pros dropped today :D But in sum it does not seem like a GPU issue since the same rendering works on the iOS sim.
Thanks!
When I have a TextField or TextEditor, tapping into it produces these two console entries about 18 times each:
CHHapticPattern.mm:487 +[CHHapticPattern patternForKey:error:]: Failed to read pattern library data: Error Domain=NSCocoaErrorDomain Code=260 "The file “hapticpatternlibrary.plist” couldn’t be opened because there is no such file." UserInfo={NSFilePath=/Library/Audio/Tunings/Generic/Haptics/Library/hapticpatternlibrary.plist, NSURL=file:///Library/Audio/Tunings/Generic/Haptics/Library/hapticpatternlibrary.plist, NSUnderlyingError=0x600000ca1b30 {Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}
<_UIKBFeedbackGenerator: 0x600003505290>: Error creating CHHapticPattern: Error Domain=NSCocoaErrorDomain Code=260 "The file “hapticpatternlibrary.plist” couldn’t be opened because there is no such file." UserInfo={NSFilePath=/Library/Audio/Tunings/Generic/Haptics/Library/hapticpatternlibrary.plist, NSURL=file:///Library/Audio/Tunings/Generic/Haptics/Library/hapticpatternlibrary.plist, NSUnderlyingError=0x600000ca1b30 {Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}
My app does not use haptics.
This doesn't appear to cause any issues, although entering text can feel a bit sluggish (even on device), but I am unable to determine relatedness. None-the-less, it definitely is a lot of log noise.
Code to reproduce in simulator (xcode 26.2; ios 26 or 18, with iPhone 16 Pro or iPhone 17 Pro):
import SwiftUI
struct ContentView: View {
@State private var textEntered: String = ""
@State private var textEntered2: String = ""
@State private var textEntered3: String = ""
var body: some View {
VStack {
Spacer()
TextField("Tap Here", text: $textEntered)
TextField("Tap Here Too", text: $textEntered2)
TextEditor(text: $textEntered3)
.overlay(RoundedRectangle(cornerRadius: 8).strokeBorder(.primary, lineWidth: 1))
.frame(height: 100)
Spacer()
}
}
}
#Preview {
ContentView()
}
Tapping back and forth in these fields generates the errors each time.
Thanks,
Steve
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.
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?
My swift student challenge submission is an iPad app built in Xcode and I'm planning on selecting the Xcode 26 option for testing in the dropdown provided in the application. Just have to confirm that the run destination for the playground in Xcode will be an iPad simulator right? Recently I have seen many participants post their submission screenshot for iPhone renders so just wanted to confirm the run destination.
Thank you👾
Hi, I was wondering if there’s a way to ensure my submission is tested on an iPad simulator in Xcode as some UI elements were designed with a large display in mind ?
Hello,
We are experiencing a recurring issue when running iOS apps in the Rosetta simulator on Xcode 26.
Environment:
Xcode: 26.0
macOS: 15.7.3
Simulator: Intel-based (Rosetta) simulators
Languages: Both Swift and Objective-C
Issue:
When launching an app in a Rosetta simulator, the app frequently freezes or fails to run. In many cases, Xcode reports that the debugger has lost connection.
Xcode error message:
Lost connection to the debugger on “iPhone 12”.
Domain: IDEDebugSessionErrorDomain
Code: 22
Failure Reason: Message from debugger: lost connection
Console log:
assertion failed: GPR thread_set_state is unimplemented for NewThread
(ThreadContextRegisterState.cpp:920 host_gpr_state_from_guest_state)
Observed behavior:
Rebuilding after fully quitting the simulator sometimes resolves the issue temporarily.
Disabling Scheme > Run > Debug executable allows the app to run normally, but debugging (breakpoints, etc.) becomes unavailable.
The issue does not occur:
On real devices
On ARM-based simulators
When building with Xcode 16 using Rosetta
Has anyone encountered this issue with Xcode 26 and Rosetta simulators? Is this a known bug, and are there any recommended workarounds besides disabling the debugger or restarting the simulator?
Thank you in advance for any insights or guidance.
Following is an error I encounter when trying to run a foundation model function in simulator.
Error Domain=FoundationModels.LanguageModelSession.GenerationError Code=-1 "(null)" UserInfo={NSMultipleUnderlyingErrorsKey=(
"Error Domain=ModelManagerServices.ModelManagerError Code=1026 "(null)" UserInfo={NSMultipleUnderlyingErrorsKey=(\n)}"
)}
Its a swift playground I'm building in xcode and works fine in the preview and on a real device too but since it's my submission for the swift student challenge I need it to run on the simulator.
I have updated my macOS to latest version of Tahoe(26.3) and Xcode is also on latest version. The simulator I run the playground is also on ios and iPadOS 26.
I have set my region to US and have turned on Apple Intelligence on my mac too.
Any suggestions on how to fix the issue?👾
Topic:
Developer Tools & Services
SubTopic:
Xcode
Tags:
Swift Student Challenge
Xcode
Simulator
Apple Intelligence
Is it possible to run an xcode cloud test with arm64 simulators NOT x86? as my app doesnt work on x86.
Since one of the last updates of XCode, there are two very annoying bugs in the simulator that just don't get fixed. What's going on Apple? You kill my productivity.
There is a red bar reading "rdar" and some numeric string at the top. You can get rid of it by going to Settings -> Developers -> Zoom -> Larger Text (then change it back). Took a while to find that.
I have a German laptop with a QWERTZ keyboard layout. Now when I type, it somehow sends keys from an US keyboard to the simulator. Since I don't have the labels, I don't know what the hell I'm typing. Very frustrating.
Please fix this.
Attempting to bring up the access point yields the following error log:
[GameCenterOverlayService] Failed to create GameOverlayUI Dashboard Remote Proxy
[GameCenterOverlayService] Could not create endpoint for service name: com.apple.GameOverlayUI.dashboard-service
[GameCenterOverlayService] Failed to create GameOverlayUI Dashboard Remote Proxy
[GameCenterOverlayService] Could not create endpoint for service name: com.apple.GameOverlayUI.dashboard-service
[GameCenterOverlayService] Failed to create GameOverlayUI Dashboard Remote Proxy
[GameCenterOverlayService] Failed to create GameOverlayUI Dashboard Remote Proxy
The same code (which is a single line setting 'active' to true) works on physical devices and on the simulator in iOS 18.6
I haven't been able to find any mention of this issue online. Any suggestions or help greatly appreciated.
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
I installed xcode 16 and both Predictive Code Completion Model and iOS 18.0 Simulator Failed Download.
I can live without the code completion, but I can not get any Simulator to install.
I clicked of the info button and it shows the following:
Download failed.
Domain: DVTDownloadableErrorDomain
Code: 41
User Info: {
DVTErrorCreationDateKey = "2024-09-30 15:57:24 +0000";
}
Download failed.
Domain: DVTDownloadableErrorDomain
Code: 41
Failed fetching catalog for assetType (com.apple.MobileAsset.iOSSimulatorRuntime), serverParameters ({
RequestedBuild = 22A3351;
})
Domain: DVTDownloadsUtilitiesErrorDomain
Code: -1
Download failed as the server said authentication failed. (Catalog download for com.apple.MobileAsset.iOSSimulatorRuntime)
Domain: com.apple.MobileAssetError.Download
Code: 41
User Info: {
checkServer = 1;
}
System Information
macOS Version 15.0 (Build 24A335)
Xcode 16.0 (23051) (Build 16A242d)
Timestamp: 2024-09-30T10:57:24-05:00
I'm running Xcode 26.2 (17C52).
After deleting all simulators and creating new ones, SwiftUI Preview stopped working.
Xcode reports:
“Simulator [D774B214-XXXX-XXXX-XXXX-XXXXXXXX8288] failed to boot and may have crashed.”
However, when I list all available simulators using xcrun simctl list, there is no simulator with that identifier. It seems Xcode is still referencing a previously deleted simulator.
I have tried:
Deleting all simulators again
Creating new simulators
Restarting Xcode and the system
But the issue persists and Preview still fails to launch.
Has anyone encountered this issue or knows how to clear the cached simulator reference used by SwiftUI Preview?
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!
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?
When I start a Simulator (iPhone 13 mini) with iOS 26 and activate "Use the Same Keyboard Language as macOS", it still sets the keyboard to US (my Mac keyboard is in German). This makes the Mac keyboard unusable. It looks like a bug, because it clearly ignores the settings. When I type “@”, I get “¬”. Restarting the simulator did nothing, changing the settings back and forth also.
BTW: Why does every single update of XCode come with a bug nowadays? I always have to spend half a day after an update to fix a problem I didn't have before. Highly frustrating.