Photos cannot be opened because of a problem
Hello everyone,
So I always back-up my photos app to an external hard drive and whenever I wanted to get those photos back I would just reopen it in my MacBook Pro. I've been doing this since 2012 till 2017. Now ever since I updated to Sierra I get the message of "Photos cannot be opened because of a problem"
Please see screenshot ... any input as to how to resolve this?
TIA