I had the same issue. I tried a lot of troubleshooting solutions like: Cleaning the Build folder; Restarting Xcode; Reinstalling Xcode (!); Deleting contents of Xcode's Derived Data folder. Nothing worked 😕 But I believe I found the solution! ☺️ Here's the fix that worked for me: Simply delete Xcode cached data. To delete Xcode cached data: Close Xcode; Open System Preferences on you Mac; Go to General tab and select Storage section; Locate Developer section (the system might take few moments to calculate the size of the files on the drive); Press on 'i' icon next to Developer section; Under Xcode Project Build Files locate cache list item (I already deleted it, so I don't remember the original name 😋 ) Delete the cache and wait for the deletion process to complete; Open Xcode. The error should disappear and everything should work as expected. This worked for me. Hope this helps!

Update: I noticed that the issue is with the view hierarchy. If I place the ProductView inside .sheet modifier and try to trigger or just place anywhere within the sheet the .fullScreenCover modifier, the app freezes when purchase is complete. If I place ProductView in a regular view (not inside a sheet), then the .fullScreenCover works fine. I tested placing a simple button inside a sheet and trigger full-screen cover, and it works fine. So the issue, as it seems, is with StoreKit API running within a sheet with fullScreenCover applied to one of the views inside that sheet

I have the same issue with the scene loading from .rcproject files. Xcode 16 doesn't seem to recognize these files as expected per this article: https://developer.apple.com/documentation/realitykit/loading-entities-from-a-file