Q: Restore photo library in yosemite

I upgraded to El Capitan. After experiencing too many issues I went back to yosemity. Now I cannot access my photo's in the photo app. I have restored the library using time time machine but after starting photo's i get a message that the library needs to be fixed. After 78% into that process I get an error message stating that the process encountered a problem and stops.

I can see the library in finder. I can access the database of the library and click on the original photo. I can even import the photo's in a new photo library. But I just want to restore the complete library automatically.

What can I do next?