I'm using Mp3Tag since a long time under Windows. It's an awesome piece of software.
Now I switched to MacOS Sierra (2.81 under WineBottler).
Everything works like a charm, but the action to rename the directory does not work for me.
I have tried various ways of writing the path (e.g. C:... or \\?\unix...), but none of them worked.
It simply returns to the main window without doing anything (also no warning).
Can you please give me a hint how to write the required path setting?
I have no Mac. So all I can give are general thoughts.
Anyway: I am not sure that an absolute path is such a good idea as the ? is an invalid character for Windows filenames.
What about a relative path? Just
%artist%\%album%
I don't know anything abou the Mac-use either.
But instead of testing this with an action I would use the converter Tag-Filename and the preview-button.
This should give yoiu at least some information instead of "nothing happens".