This was posted elsewhere, and I realized that my response should be in the software forum so I simply copied the postings over here. My post: I am also having a similar problem with the System Preferences. I have opened the Desktop & Screen Saver preferences. I am trying to set up a mosaic screening saver but an error message comes up that I must have an iPhoto library (I do!) to select from. I also have to Force Quit the System Preferences. Restarted but same problem occurs! Help!