Cannot write tags to M4A files

Continuing the discussion from "Cannot write tags to file x in folder y" error:

Same problem here. To all questions above: no. It's not the file, because other files from the same album don't give this error. (Audirvana is able to edit the tag.)
This error occurs with a lot of files, mainly Apple Lossless Audo (m4a). But on the other hand, many m4a files do not cause any problems. It's also not the settings of the MacBook, because they are the same for all files in the album.
Please no further questions, just a solution.

Can you try this command via Terminal.app while Mp3tag being closed:

defaults delete app.mp3tag.Mp3tag SecurityScopedBookmarks

After that, load the folder (not the individual files) via ⌘O and see if the issue persists.

Thank you for your swift response. Unfortunately it doesn't work.

OK, then the error has some kind of mysterious cause. Could you try and see if Console.app (set to streaming) produces any details on that error?

BackLog is another option, where you can set the process to Mp3tag and include all events that are not directly created by this binary.

The idea of this is to gather some information on what's causing the issue (as it doesn't seem to be related to secure bookmarks).

Maybe one additional question: are the files on your local Mac or on any external medium?

Thanks!