I don't know if this is of any interest anymore, but I thought I would follow up on some related problems. I finished debugging the app (it is not intended to be submitted to the app store and is signed locally) and went to create a release version for my own personal use.. Then I got a repeat of the failed try in FileManager. I switched back to the debug version and again the try failed. I turned off debugging and tried again. No try failure. I turned back on the debugging and the try failure was still gone. So this looks like this is an xcode problem related to debugging. In any case, I have my release verrsion installed and it works fine.
Topic:
App & System Services
SubTopic:
Core OS