Follow these steps to use the Photos library repair tool:
- Hold down the Option and Command keys while you open Photos on your Mac.
- In the dialog that appears, click Repair to start the repair process.
You might be asked to type in your user account password to authorize the library repair.
The repair tool analyzes the the library's database and repairs any inconsistencies it detects. Depending on the size of your library, this might take some time. When the process is completed, Photos opens the library.
If you repair a library that's automatically updated with iCloud Photos, the entire contents of the library re-updates with iCloud after the repair process completes.