Find duplicate items in Music on Mac
You can find every instance of a song by the same artist anywhere in your music library. For example, the same song could appear on the artist’s album and on a movie soundtrack.
You can also search for exact duplicates, in which a song, artist, album and version are all the same (if, for example, you inadvertently imported a song twice).
In the Music app
on your Mac, click Songs in the sidebar on the left.
Select an item, then do one of the following:
Find every instance of that item in your library: Choose File > Library > Show Duplicate Items.
Find exact duplicates: Hold down the Option key, then choose File > Library > Show Exact Duplicate Items.
After you find duplicate items, you can delete them if you want to declutter your library.
To see all items again, click Done in the bottom-right corner or choose File > Library > Show All Items.