I purchased MP3Tag a couple of weeks ago and have been using it flawlessly until today. Now I get an error message saying it's "Not Supported on This Mac". I haven't upgraded anything since I started using MP3Tag, so I'm at a loss.
I restored the app and it's working again. Never saw that happen before. The app icon even had a circle with slash.
Glad it's back working again! Not sure why that happened — I've also never saw this before.
There is a support document by Apple
but it looks more like a permission issue as outlined here