I recently installed a 1 TB SSD into my Roon Nuc and then copied and pasted my music files from an Airport Time Capsul that has 1 TB drive built in. The problem is some of the files have multiple copies of each song (usually 3 copies) on the file, but some files do not.
A screenshot of the duplicate albums would help as well and you can check to see if they’re in different file paths by Right Clicking a track -> 3-dot drop-down menu at the top -> View File Info. It should display a screen similar to this:
Here are 3 screen shots of the View File Info for 1 song. Not all the album/files duplicate the songs. The files that do duplicate the songs sometimes duplicate them twice and other times 3 times.