How to Rebuild/Repair an iPhoto Library
 

If iPhoto fails to load or crashes on startup, you may need to repair and rebuild you iPhoto library.

To rebuild an iPhoto Library hold down the option and the command key and click on iPhoto to launch the application.

Hold down the option key when starting iPhoto

iPhoto will appear with the following dialog box.

iPhoto Rebuild/Repair prompt

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.

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.

Rebuild Database

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.