Xcode auto updated today on sept 17 to version 16.
All apps crash with XCBBuildService quit unexpectedly unexpected service error: The Xcode build system has crashed. Build again to continue.
I see various posts about this about beta.
But having your prod release crash 100% of the time after you auto push to everyone seems "short sighted" to say the least.
Fix: https://xcodereleases.com/?scope=release
hit "download" for 15.4
and turn off system settings>general>software update> and turn off auto updates for App Store
and don't forget to do this after you get a new machine, like I did.