Cannot write tags to some M4a files

Support
1

Using MP3Tag to clean-up my library and found some M4a files that MP3tag could not read or write tags for. Did a search of the forumand it looks like this may have occurred previously but with m4v video files. As an FYI, I can read / write tags in itunes v10.1. I thought maybe the tags were corruptso I tried to use ID3Killl to clear all the tags but that didn't do anything.

Also tried another editor, TagScanner v5.1, and it cannot read / write tags for the files either. So this may not be a "bug" in MP3Tag.

Anyone got any ideas?

2

are you sure these don't have DRM?

3

All tracks on the album are edittable except for one. The tracks were DL'd from iTunes recently so they should have any DRM as iTunes has removed / stopped using it haven't they?

4

yes, that's my understanding (about itunes and DRM). No other clues on my end.