iTunes 12.9.5.5 not loading all music

Hi,

I'm having a problem with iTunes 12.9.5.5. It's not loading all of the music from the library.

I recently had to reinstall the OS from a Catalina debacle and get everything back up to Mojave, so iTunes was wiped and reinstalled. My music is on a thumb drive, so it was unaffected. I loaded I tunes, pointed it at the right folder on my thumb drive, but not all music will load. It's there in the folder but won't appear in the iTunes window. I didn't have a problem with this setup until now.

It looks like the only music loading is purchased music. I checked the settings and the "All Music" view is checked. I tried resetting the link to the music folder to the HD and then setting it again to the thumb drive. I don't know what else to do. Anyone have a fix for this?

Thanks,

Holly