Remove Duplicate Songs from iTunes
If you have a large iTunes library it’s really easy to inadvertently gather duplicate songs. Thankfully cleaning up and removing the duplicates from the iTunes song library is really easy, here’s how to do it:
Removing Duplicate Songs from iTunes
* Within iTunes open the ‘File’ menu
* Navigate down to ‘Show Duplicates’ (see below screenshot)
* iTunes will now show what it thinks are duplicates
This method does not always work though to find true duplicates of songs and will sometimes give you songs that are just very similar in name or artist, so you may want to try this instead:
Remove Exact Duplicates from iTunes Song Library
* Hold down the Option / ALT key
* Navigate to “File” menu
* Click on ‘Show Exact Duplicates’
* Now iTunes will display ONLY the exact duplicates (see screenshot)
This list shows you the songs that iTunes thinks are duplicates, so do not delete everything in the list or else you may delete the original song that you want to keep. iTunes isn’t perfect in detecting duplicates either, it looks like it bases most of the detection on song, artist, and album names, so if you have two songs named the exact same thing but they are different iTunes will likely think it is a duplicate.
After you have cleaned up your duplicate songs, you can get the iTunes library looking like normal again by clicking the ‘Show All’ button that is highlighted in the above screenshot, or simply navigate back to the ‘File’ menu and click on ‘Show All’ where “Show Duplicates” once was.
This works in many versions of Mac OS X 
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