A good news. I have just read this article on 9to5mac.
http://9to5mac.com/2012/10/01/iphoto-for-mac-about-to-get-much-needed-bug-fixes/
In the coming days, iPhoto for Mac will see an update that focuses on major bug fixes. The current version, 9.4, was released alongside OS X Mountain Lion. We’ve heard many reports from readers having issues syncing photos to their iOS devices via iTunes. Some users also reported random iPhoto for Mac crashes. Apple will fix both of these issues and more per the release notes of iPhoto 9.4.1:
-Improves the reliability of syncing to iOS devices via iTunes.
-Fixes an issue that could cause iPhoto to quit unexpectedly when using the Export command.
-Addresses an issue that could cause iPhoto to quit unexpectedly when upgrading calendars, multiple books, and cards.
-Resolves an issue with viewing and downloading photos synced via Facebook albums.
I know some of you don't use iPhoto, but it might be the cause.