"Photo library is locked or you do not have the necessary permissions" after Catalina upgrade
I store my Photos library on an external drive. After the Catalina upgrade, I receive the message "Photo library is locked or you do not have the necessary permissions" when attempting to open the the library with Photos. The Photos repair tool fails. I have the library backed up with Carbonite, but I'm concerned that the version I restore will have the same problem. (I'm downloading the backup to my desktop now; it has not finished downloading from Carbonite servers yet.) Has anyone solved this issue?
MacBook Air 13", macOS 10.15