Because of the problem of iTunes adding DRM to your music files if you have an Apple Music subscription, iTunes users need a way to determine which files are theirs, which they have downloaded from Apple Music, which are matched, which are uploaded, and so on.
You can do this with a smart playlist. In iTunes, choose File > New > Smart Playlist. Choose iCloud Status in the in the first menu. You’ll then be able to choose from a number of options in the third menu:
- Matched tracks have been matched by iTunes Match or Apple Music. These files are in your iTunes library.
- Purchased tracks are those you’ve bought from the iTunes Store. They are either in your local library or in the cloud.
- Ineligible tracks are those with bit rates too low (below 96 kbps), or sizes that are too large (over 200 MB), files that weren’t purchased with your Apple ID, and other non-music files.
- Local Only tracks are those that you have removed from iCloud but remain in your local iTunes library.
- Error indicates files where something went wrong.
- Duplicate files are those you have more than once in your library.
- Apple Music files are those you’ve either downloaded from Apple Music for offline listening, or files that you’ve matched with Apple Music, and then downloaded.
Unfortunately, there’s no way of knowing which of these Apple Music files were yours in the first place. So keep a backup of your original files, and don’t delete any local files and replace them with Apple Music backups.