Charles has upgraded to macOS Catalina 15.1, and now he's getting crashing due to an error with an iOS device. Leo suspects it may be a wifi sync issue between Charles' iPad and the Mac. So into the music settings and turn off sync library and see if that solves the issue. It sounds like a bug that Apple has to fix. Also, try opening the Activity Monitor. It'll show what processes are running and when you shut down, kill the sync process. That's not a great solution long term, but it could work until the fix comes in a future update. A complete clean install may also fix it.