Before you use the Photos Repair Library tool, back up your photo library. You can use Time Machine, use a third-party backup solution or copy the library to an external drive. By default, your photo library is stored in the Pictures folder within your home folder.
To get to the Photos Repair Library tool on your Mac, follow these steps:
- If Photos is open, close the app. Then while you're clicking to open Photos, hold down the Command and Option keys at the same time.
- In the window that opens, click Repair to start the repair process. You may be asked to enter the password for your user account.
The Repair Library tool analyses the library's database and repairs any inconsistencies it detects. Depending on the size of your library, the repairs may take some time. When the process has finished, Photos will open the library.
If you're repairing a library that's used with iCloud Photos, iCloud will check the library after the repair process has completed to ensure everything has synced correctly.
If these steps haven't worked or you can't open the repair tool, contact Apple Support.