(Posting this here because I don't think this was due to MusicBee...)
So, a while back I had a tag meltdown - for lack of a better word. I lost the tagging info of about 1000-1500 mp3s (of a total of 15000 or so at the time) - and I'm not really sure what happened. Or I didn't lose them per say, but the affected mp3s had their tags revereted to ID3v1.
It *might* have been me doing an automated update of last.fm keyword tags through MB, but it might also have been the Nokia Music Player that messed stuff up when it "optimized album covers" (I have since stopped using NMP since MB transfers files much easier to my phone - go figure).
There doesn't seem to have been any particular pattern to which mp3s got their tags decimated - in some cases whole albums were nuked, in some cases only a bunch of tracks got it. I'm also not sure if it only hit tracks that got their keywords updated or not.
Anyways, I've since re-entered the lost info on most of the tracks - but the problem comes with BPM detection. I can't seem to generate BPM numbers for the affected tracks. Generally I use MixMeister and it just doesn't recalculate the BPM for those tracks. So I tried PistonSoft's BPM detector as well - with no luck. I've looked in the tag inspector and I really can't see anything that differs between previously affected mp3s and unaffected ones (I particularly checked the id3 tag version - I'm using id3v2.4). Also tried deleting the value in BPM/TBPM but that didn't do anything.
Sorry if this is a bit incoherent, this wasn't as easy to explain as I thought it would be...
Edit: Oh, so yeah... basically what I'm wondering is - has this happened to anyone else? Anyone know what I could do about it - other than re-encoding those files..?