Repair your library in Photos on Mac
If you experience problems with photos in a library, you can try to repair it.
Important: Make sure to back up your photo library before repairing it.
If the Photos app on your Mac is open, choose Photos > Quit Photos.
Press Option-Command and double-click the Photos icon in the Applications folder (or Option-Command click the Photos icon in the Dock).
In the Repair Library window, click Repair to rebuild your photo library.
If problems persist, you can also restore your library from a Time Machine backup.