Was trying to format a USB stick the other day using the Disk Utility, but it wouldn't open. Instead I got an error "Disk Utility cannot be opened because of a problem". So I thought I would create a new account and see if the Disk Utility was working using a new account. (I only have 1 account) I tried to open the Accounts preferences pane. Only to receive the message "To use the "Accounts" preferences pane, System Preferences must quit and re-open". Upon system preferences re-opening I received an Preferences Error "Could not load Accounts preferences pane". So I turned to the forums, I deleted com.apple.DiskUtility.plist in my user drive and system library. Also deleted Accounts Pane equivalent. Restarted my MBP and still neither Disk Utility or Accounts Pane worked. I also tried Pacifist, I re-installed both Disk Utility and Accounts Pane. I even tried installing the Disk Utility to a different located (not Utilities folder) and still I receive the same errors. I think I have to re-format my HD and re-install OS X. Any ideas that doesn't involve re-installing OS X?