Delete duplicates find records that appear to be the same song and marks for deletions all the duplicates, no records are actually deleted until changes are saved. By default Jaikoz identifies duplicates by looking for files with duplicate MusicBrainz Ids , but in the preferences you can change this to find duplicates based on their AmpliFIND Id or their MusicBrainz Id AND Music Ip Id. Jaikoz compares the duplicate files by their Audio Format, Bitrate, File size and Track Duration and deletes the files with the lowest quality. More information at Deleting Duplicates