Hi everyone, let me just preface by saying I apologize if this question and answer have already been posted somewhere else, the search function was down and therefore I wasn't able to do my due diligence. That being said... I have a new, late 2011 21.5" iMac that runs beautifully except for one thing; it will not complete either a restart or shutdown process. The system will log me out of the user account and it will get to they grey screen with the spinner like its going to shut down or restart but then it will just lag there for as long as I let it. In an experiment one night I left it "shutting down" while I went to bed. When I got up 9 hours later it was still in the exact same part of the process as it was when I shut my eyes. What is causing this, and please tell me that there is a very simple solution to this annoying glitch. I'm guessing that the answer is a wipe and reload of the OS (Mountain Lion btw) but I'm praying that there is a simpler solution. Any help anyone can provide is greatly appreciated. Thanks in advance!