The "Display Duplicates" has been omitted from File selections in iTunes 11.0
interesting I am looking at that now. I'll let you know if i find it somewhere.
You should probably ask this in the iTunes forum. This is the iPhone forum.
Two Windows scripts to make playlists of Duplicates and Exact Duplicates. Use shift-delete to remove selected tracks from the library as well as the playlist.
There is also my DeDuper script if you don't want to do it by hand. Please take note of the warning to backup your library before deduping. See this thread for background.
Retrieving data ...