I have a few M4A files downloaded fro a site called Beatport. Having a tricky time tagging them. From memory, I think at first I could not tag them with MP3Tag, then I could with a new release (can't remember which), now I can't again. If I look at the files in MP3Tag, they are displayed correctly. But any editing blows the tags away and I can't re-tag. Also makes the tracks unrecognisable (as audio tracks - i.e. I can't import them) in iTunes.
Strangely though, I can edit the tags (of the original files) in iTunes. Anyone else seeing this behaviour? Any comments as to why appreciated.