Godot application not working for others. Check your log file

I've build a few iterations and suddenly it is broken. What!

Checking with the log file showed an error on a audio file name.

open ~/Library/Application Support/Godot/app_userdata/my-game/logs/godot.log

contains

...
**ERROR**: Cannot load source code from file 'res://UI/Audio.gd'.
...

So ... moving code from project using UI in uppercase to on that has ui lowercase is a known MacOS problem.