I have Rhythmbox 2.97 on 32bit Ubuntu 12.10. I have a large number of duplicate music entries that don't show up in my music folder. Just Rhythmbox. I really would like to know if there's any plugin or ant means to get rid of them.
It's happened to me a few times...
The easy way to solve this issue is:
The rhythmdb.xml file contains the music library info for Rhythmbox, by deleting it, you'll be forcing rhythmbox to re-check the library, thus getting rid of the repeated entries.