After nuking these two items I was able to install Metal on macOS Sequoia 15.6. sudo defaults delete com.apple.MobileAsset EnableLiveAssetServerV2-com.apple.MobileAsset.MetalToolchain sudo defaults delete com.apple.MobileAsset PallasUrlOverrideV2-com.apple.MobileAsset.MetalToolchain Thank you.

So the problem is a few threads reported this about 48 hours ago. Yesterday an 'Apple' person dropped on the threads it was 'fixed' but I have not been able to fix it with anything I've tried. The struggle is real. :-(

This fails regardless of which Xcode bundle you select (Universal / Apple Silicon). It also fails for Mac OS 15.6 and Mac OS 26 Beta 5. I've found no work around for this and no CLI option to get past this either. This is a blocking issue for anyone with Metal in their App. Please advise.

I have the same issue.

The odd thing is work isn't letting us on the latest MacOS. If I connect my developer phone to my home system on Mac Sonoma I can download with no issues. On my work laptop that is running Ventura 13.6, after the 17.0.3 update I get the dreaded: Previous preparation error: The developer disk image could not be mounted on this device.. Error mounting image: 0xe8000105 (kAMDMobileImageMounterTATSUDeclinedAuthorization: The server declined to authorize this image on this device for this user.) My guess is the crypto is out of what between the two Mac OS versions. The dialog above will also bounce to this after a few seconds and then bounce back: "Xcode will continue when the operation completes." Anyone gotten a work around with Xcode 15 on Ventura 13.6? Thanks!