Several Mac users have reported iPhoto problems in OS X Snow Leopard, where the app refuses to open or crashes. Here is what to do.

1. Put the iPhoto.app in the trash (Drag it from your Applications Folder to the trash)
2. Go to HD/Library/Receipts and remove any pkg file there with iPhoto in the name
3. Re-install.
• If you purchased an iLife Disk, then iPhoto is on it.
• It will also be on the System Restore disks that came with your Mac. Insert the first disk and opt to ‘Install Bundled Applications Only…’

1. Trash the com.apple.iPhoto.plist file from the HD/Users/ Your Name / library / preferences folder.
2. You’ll need to reset your User options afterwards. (These include minor settings like the window colour and so on.)
3. If you’ve moved your library you’ll need to tell iPhoto where this is.

If that also fails:

Post the Crash Log in Apple Support.

1. Get the crash log from Home / Library / Logs / Crash-Reporter / iphoto.crash.log
2. Double click on the file and it will open in the Console.
3. Copy and Paste the contents here, at bottom of this discussion.

From: iPhoto won’t open since Snow Leopard…: Apple Support Communities.