Some users that purchased iLife 11, which includes iPhoto 11, reported that their photos were lost or corrupted when the application tried to update their image library. Just like previous iPhoto releases, the new version requires a different database format, and the application performs the update the first time it’s launched.
The iPhoto 11 version 9.0.1 update is free and available via the Software Update application, or as a downloadable installer via the Apple Support Web site.