iPhoto '11: If you see a message that iPhoto can’t access one or more photo files
When you try to open or upgrade iPhoto, you might see a message like this:
“There is a problem accessing one or more files in your iPhoto Library folder. Do you want iPhoto to repair permissions for this library for you?”
This usually means that one or more of the iPhoto files or folders are locked or the settings don’t give permission for opening or editing them.
To correct a permissions issue:
Quit iPhoto, if it’s open.
Hold down the Command and Option keys as you click the iPhoto icon.
The Photo Library First Aid window opens.
Click Repair Permissions to repair permissions and unlock necessary files and folders.
For information about the remaining checkboxes, visit the iPhoto Support website.
It may take a few moments for iPhoto to finish checking your library for permissions errors and locked files or folders. When iPhoto opens, you should be able to use your iPhoto library.