reclaiming lost space on card
just some extra info regarding this issue
before I knew about the delete msmedata file solution I found that when I tried to update the library it would seem to hang the phone while adding files. While this was happening I looked at the available memory on the card and saw it quickly running down to 0mb. It was as if the phone was trying to copy duplicates of all my audio files. I could not find these files even though they were obviously taking up the space on the card, and so could not delete them. The only way I could reclaim this space was to back up the files that I did want, formatted the card and finally copied the wanted files back onto the card. Space reclaimed.
Maybe there's a simpler work around for this that I am unaware of but if not, I hope this helps someone.
They Made Me Do It