Photos - Cannot open migrated library
I am running macOS Catalina10.15.6 on my MacBook Pro
Since I upgraded to Catalina (from High Sierra) I have not been able to view at any of my old photos.
When I click on Photos I get the message in the screen shot
It could be a consequence of iPhotos or they could be stored somewhere else on the Mac but I had circa 1000 photos. Any help welcome or is there a tool I could use. I regularly use time machine so depending on how far it goes back I could look - any help welcome
MacBook Pro 15″, macOS 10.15