Songbird has changed my tags, altered my playlists and given songs the wrong album art

Started Songbird up as normal, didn't do anything out of the ordinary. Once my library has loaded up, I find that the tags for many songs in my library have changed and that the content of my playlists has been altered. The tags don't seem to have changed on the actual files themselves, only in Songbird. No idea why this would happen. I'm not running the Media Management mode on Songbird either. Actually, it's not just the tags but the album art too. Artist, album, album artist, genre, album art: some or all of these have been changed on what I would estimate to be 20% of my library. Any ideas about how to go about changing this or making sure it doesn't happen again? It's pretty frustrating.

Apologies if this has been asked before. I did look but couldn't see anything quite like the problem I'm describing here.

Btw, I'm running Windows Vista and Songbird 1.2

Thanks.