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)