OS X 10.8 or later. This application will list the file paths of the files in your designated "iTunes Media" folder which are not in iTunes' track library. Additionally, you can select a different parent folder and its contents will be compared to the iTunes library. Includes options to Add a selection of found files to iTunes, move them to the Trash, and export a text file listing the file paths.
See the video on YouTube.
These files are in my "iTunes Media" folder but do not exist as track entries in iTunes. The tracks may have been deleted from iTunes but, for whatever reason, I did not choose to move their files to the Trash.
Change file type to make selected AACs bookmarkable
List tracks not assigned to playlists
Exports and then re-imports selected tracks' artwork
Display, create text file listing info of dead tracks
Re-associate batch of dead tracks with files from selected folder
Two scripts copy text from clipboard to current or single selected track's lyrics tag