Fix a Photos library that won't open with Repair Library

Why it happens

Photos keeps all your pictures and their details in one library. If your Mac shut down suddenly, the disk filled up or something interrupted Photos while it was saving, the library's records can get damaged. Photos may then hang, quit or show blank thumbnails, and Repair Library checks the library and fixes the problems it finds.

How to fix it

1. Back up first, for example with Time Machine, so you have a copy of the library whatever happens.

2. Quit Photos with Command-Q. If it's frozen, open the Apple menu, choose Force Quit, pick Photos and click Force Quit.

3. Hold down Option and Command, then click Photos in the Dock or in your Applications folder. Keep holding both keys until the Repair Library window appears.

4. Click Repair. Your Mac may ask for your login password.

   Photos›Repair Library›Repair

5. Let it finish, which can take a long time for a big library. Keep a MacBook plugged in. When it's done, the library opens. If you use iCloud Photos, give it time to catch up with iCloud afterwards.

Still not fixed?

1. Photos needs free space to work. Check how much your Mac has in General > Storage and make room if it's nearly full.

   General›Storage

2. To find out whether the problem is the library or Photos itself, hold Option while you open Photos. In the window that appears, click Create New… to make an empty test library. If that opens fine, the problem is in your old library.

3. Install any waiting macOS update in General > Software Update, then try Photos again.

   General›Software Update

4. If Repair can't fix it, restore the Photos Library from your Time Machine backup. It's in the Pictures folder of your home folder unless you moved it.

5. If Repair keeps failing, or the drive that holds the library shows errors in Disk Utility's First Aid, the drive may be failing. Stop saving to it and contact Apple Support or a repair shop, as it may be hardware.