iTunes 12.1.0.50 import problem

Hi, I just did a clean install of OS X Yosemite (latest version) to update my intel iMac. It seemed to work well.

Then it took about 56 hours to import and organise my iPhoto files from back up, but we finally got there.

Now I'm trying to import my iTunes library (using iTunes import function) from a backup disk but it doesn't seem to be working. I can see in Finder that all the music has been copied to the iTunes music folder that i expect it to. But none of it is showing up in the iTunes music screen. The only way I can get it to show up is by clicking on a song in Finder and having it play. Most of this music was purchased over the past few decades but not via iTunes (the iTunes songs on iCloud seem to be acting as i'd expect).

Can anyone help with how to get all my songs to show up in the iTunes music page after import? I don't want to have to click and play every single one of them, there are lots and lots.

I didn't try archiving my iTunes directory when I backed it up, just used copy and paste. I'm wondering whether i should have done the reverse to bring the music back in.

Thanks in advance.