Dupin is an iTunes duplicates manager. iTunes' "Show Duplicates" feature is helpful but you still have to examine every track to determine whether you want to keep or delete the tracks it finds. Smart Playlists are of dubious help and trying to locate all duplicates with them can be tedious as they can quickly crowd your Source list and slow iTunes down.

Now there's Dupin.

Features:

• Very quickly find all sets of duplicate iTunes tracks based on your choice of criteria
• Select the "Keeper" tracks from among a number of duplicates automatically using a variety of versatile filtering options
• Consolidate the play, skip, and ratings information from all tracks in a Dupe Group to the single "Keeper" track
• Re-populate iTunes playlists replacing "non-Keeper" tracks with "Keeper" tracks
• Remove duplicate tracks from iTunes and send files to the Trash
• Manage intentionally duplicated tracks
• Copy tracks to new iTunes playlists
• View duplicates in non-loaded libraries created with iTunes' multiple library feature
• View duplicates in iTunes libraries on other machines on your local network
• Sort tracks and view track info
• Export a list of duplicates to a text file
• Locate tracks in the Finder and in iTunes
• Audition tracks

Limitations: The unregistered demo version of Dupin will display up to 20 sets of duplicate tracks and allow one Purge per session. All other features are unencumbered.

Dupin Lite has the same powerful Get Dupes-Filter-and-Purge features as the original Dupin but with fewer power-user features. If you aren't interested in managing duplicate tracks as much as just identifying and eliminating them then Dupin Lite may be right for you. Dupin Lite is available for $7.99 from the Mac App Store

Requirements:
OS X 10.8+
iTunes 11+
64-bit Intel