Sometimes, multi-disc sets will appear as separate "albums" in your library, with text like "disc 1" appended to the album name for each disc. It is preferable to MERGE these multi-disc sets into one "album" with unique disc numbers assigned in the metadata:
1. Open the Smart Tag Editor utility and locate a multi-disc set that should be merged. Tip: search "disc" and the app will pull up albums with the word "disc" in the title...many of the items you'll want to edit will meet this search criteria.
2. Press & hold on disc one of the set, then tap on the other disc(s) that you want to merge into one:
3. Press "merge" (upper left of screen)
4. Confirm that the correct disc numbers are assigned accordingly:
5. Name the album properly (omit any "disc 1" "disc 2" extraneous info:
6. Press "Done" and the albums are now merged into one set.