I need to merge two photo libraries, but it says one needs to be repaired when it doesn't
I used dropbox to move all my stuff from an older computer to a new one. But it didn't get (all) the photos and music. I put those folders inside dropbox temporarily to bring everything over. But that created a 2nd photos library. Now Photos claims it needs to be repaired. It doesn't. I can open the newer or older one by opening Photos with the option key pressed. Both work fine.
This 1st screenshot shows what I'm trying to do, including the filename.
This 2nd screenshot shows the error message I get.