Photos
I have recently updated my iMac to Mojave. Then I migrated my iPhoto library (27000 photos) to photos. Photos is running so slowly. Almost a constant spinning wheel. I don't use iCloud except for photo stream. I want to sync my devices through iTunes and recently that has been a nightmare. Thought if I used Photos it would fix the issue. But I don't know because I have so much clean up to do with events and faces. And the almost constant spinning wheel in photos is driving me crazy. Says it is updating people in the background but it has been a couple of weeks. Help! (I also hate that you cannot delete faces that photo had identified - like in large group photos or even photos on the wall in pictures)
iMac Line (2012 and Later)