Blocker: Registering simulator runtime with CoreSimulator failed.

Hello,

FWIW I've been developing enterprise iOS apps going on 10 years and haven't seen a bug like this. It's a major blocker. Any advice is welcome.

Pulled latest from my team's repository . I ran into a build issue. Reinstalled cocoa pods, resolved swift packages, cleared cache, and then tried to update my iOS simulators... Since then, everything is bricked. Can't side load an app or download a simulator.

When I try to download simulator, as suggested by Xcode, I receive the following error:

Registering simulator runtime with CoreSimulator failed. Domain: DVTDownloadableErrorDomain Code: 29 User Info: { DVTErrorCreationDateKey = "2025-05-28 19:18:13 +0000"; }

Registering simulator runtime with CoreSimulator failed. Domain: DVTDownloadableErrorDomain Code: 29

Mount failed: SUIS premount dissented Domain: com.apple.CoreSimulator.simdiskimaged.SimDiskImageError Code: 10 Failure Reason: the operation is not appropriate (kDAReturnNotPermitted)

System Information

macOS Version 15.5 (Build 24F74) Xcode 16.3 (23785) (Build 16E140) Timestamp: 2025-05-28T14:18:13-05:00

I've restarted my Mac. I've cleared caches. I cleared project builds and all old simulators. I've reverted to much older previous commits after trying above just in case (even though I've verified no one else on my team is experiencing this issue). Nothing works.

I found a post online and tried this command: xcrun devicectl manage ddis update

Resulting in this:

Host CoreDevice version: 443.19 13:57:32 Updating host DDIs. 13:57:32 Failed to update the host's developer disk images. ERROR: Failed to update developer disk images on the host. (com.apple.dt.CoreDeviceError error 12010 (0x2EEA))

ERROR: Request to update the host's developer disk images failed. (com.apple.dt.CoreDeviceError error 12013 (0x2EED))

ERROR: Failed to update developer disk images on the host. (com.apple.dt.CoreDeviceError error 12010 (0x2EEA))

ERROR: Failed to copy a developer disk image to the underlying system. (com.apple.dt.CoreDeviceError error 12009 (0x2EE9)) NSURL = file:///Library/Developer/CoreDevice/CandidateDDIs/iOS_DDI.dmg DeveloperDiskImageInstallLocation = file:///Library/Developer/DeveloperDiskImages_2D128D6A-770D-4040-8819-C611DC607098.staged/

ERROR: The developer disk image could not be staged on the host. (com.apple.dt.CoreDeviceError error 12045 (0x2F0D)) NSURL = file:///Library/Developer/CoreDevice/CandidateDDIs/iOS_DDI.dmg

ERROR: The operation couldn’t be completed. StorageKit claimed that it mounted the disk image at the required path, but the item there is not a disk image. (NSPOSIXErrorDomain error 2 (0x02)) ExpectedMountPoint = /private/var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/T/28C3C798-5FB7-45E6-A95C-4CC84A3D7851 NSLocalizedFailureReason = StorageKit claimed that it mounted the disk image at the required path, but the item there is not a disk image. NSURL = file:///Library/Developer/CoreDevice/CandidateDDIs/iOS_DDI.dmg NSLocalizedRecoverySuggestion = This is likely due to a software bug. Please file a bug report including a sysdiagnose.

Also, here is the latest from my CoreSimulator logs:

May 28 13:50:24 Mac com.apple.ibtool[3680] <Warning>: Unable to discover any Simulator runtimes. Developer Directory is /Applications/Xcode_16.3.app/Contents/Developer. May 28 13:52:10 Mac com.apple.CoreSimulator.simctl[4509] <Warning>: Unable to discover any Simulator runtimes. Developer Directory is /Applications/Xcode.app/Contents/Developer. May 28 13:52:44 Mac com.apple.dt.Xcode[948] <Error>: Adding runtime disk image '/System/Library/AssetsV2/com_apple_MobileAsset_iOSSimulatorRuntime/6fb1e5fe25ee1c372f7116516e615c556906bd4e.asset/AssetData/090-44150-318.dmg' error: Error Domain=com.apple.CoreSimulator.simdiskimaged.SimDiskImageError Code=10 "Mount failed: SUIS premount dissented" UserInfo={NSLocalizedDescription=Mount failed: SUIS premount dissented, NSLocalizedFailureReason=the operation is not appropriate (kDAReturnNotPermitted)} May 28 13:53:35 Mac com.apple.dt.Xcode[948] <Error>: Adding runtime disk image '/System/Library/AssetsV2/com_apple_MobileAsset_iOSSimulatorRuntime/6fb1e5fe25ee1c372f7116516e615c556906bd4e.asset/AssetData/090-44150-318.dmg' error: Error Domain=com.apple.CoreSimulator.simdiskimaged.SimDiskImageError Code=10 "Mount failed: SUIS premount dissented" UserInfo={NSLocalizedDescription=Mount failed: SUIS premount dissented, NSLocalizedFailureReason=the operation is not appropriate (kDAReturnNotPermitted)} May 28 14:21:02 Mac com.apple.dt.Xcode[948] <Error>: Adding runtime disk image '/System/Library/AssetsV2/com_apple_MobileAsset_iOSSimulatorRuntime/6fb1e5fe25ee1c372f7116516e615c556906bd4e.asset/AssetData/090-44150-318.dmg' error: Error Domain=com.apple.CoreSimulator.simdiskimaged.SimDiskImageError Code=10 "Mount failed: SUIS premount dissented" UserInfo={NSLocalizedDescription=Mount failed: SUIS premount dissented, NSLocalizedFailureReason=the operation is not appropriate (kDAReturnNotPermitted)}

I appreciate any help. Thank you

Turns out it was an MDM policy.

Blocker: Registering simulator runtime with CoreSimulator failed.
 
 
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