I'm having the same issue. I'm getting the same error message: (realitytool.RKAssetsCompiler.RKAssetsCompilerError error 3). I'm not sure what is causing it though, as I can't find any of those warnings about missing texture files. I'm trying to develop an app that will run on iOS, iPadOS and VisionOS, so I'd really like to get this sample app running!

Ive been having the same issue. Xcode 16, iOS and iPadOS 18. Seems to get stuck quite often on "Preparing iPad" (or "Preparing iPhone"). The only solution I've found is to disconnect the cable, reboot my MacBook, and re-connect the cable. Also rebooting the iPhone/iPad seems helps to keep it from happening quite as frequently (although it still happens a lot). Gets a bit frustrating having to reboot all the time.