If iPhoto fails to load or crashes on startup, you may need to repair and rebuild you iPhoto library.
Launch the Photos app. In the lower-left corner of the app, press the Settings button. Midway down the Settings page, you can see a section called Sources. Clicking the X buttons to the right of the folders removes them, and clicking 'Add a folder' allows you to pick new folders to include in your collection.
To rebuild an iPhoto Library hold down the option and the command key and click on iPhoto to launch the application.
iPhoto will appear with the following dialog box.
- Photos has attempted to repair the library Photos Library.photoslibrary but is unable to open it. The most common cause of this is a permissions problem. Not necessarily that you don’t have the permission, as Photos will prompt for administrator permissions if that’s simply the case, but that permissions can’t be obtained, even with.
- Apple’s Photos Library repair tool detects any discrepancy in the library’s database and repairs the same. Depending on the number and size of your library photos, and the network speed, the process might take some time. For instance, a 150GB photo library may take about 24 hours. So you need to be patient to get it finished.
- To rebuild an iPhoto Library, simply hold down the option and the command key and click on iPhoto to launch the application. IPhoto will appear with the following dialog box. Depending on what is erroneous with your iPhoto library, opt for one of these options.
- My suggestion: start with “Repair Permissions” and work your way down the list, stopping after each procedure to see if your photo library has reappeared. As you move down the fix-it list, the repair work gets more and more involved, with “Rebuild Database” being the most intrusive and labor-intensive (on iPhoto’s part, not yours).
Depending on what is wrong with your iPhoto library select one of these options.
Repair Permissions
This is probably the best option to start with. If your computer was not shutdown correctly, there may be files that were left open at the time. Repair permission fixes this problem.
How To Rebuild Photos Library
Rebuild Thumbnails
iPhoto may have missing or damaged temporary images that iPhoto needs. This option creates those images again.
Repair Database
If the photos in your library don't match what iPhoto thinks it should be, this option will fix that problem. iPhoto looks at what photos are in the library and updates its records accordingly.
Mac Rebuild Photos Library
Rebuild Database
Rebuild Photos Library
If nothing else works, use this option. It may take a long time and you might lose information about the photos or albums. Try all of the other options before using this one.