The reason I asked is because after letting my Mac Pro in my studio sit (turned on) for some time without use I found it yesterday with the perpetual gear running over the screen saver and the Mac would not respond. That's good advice Nigel and something that I generally adhere to. so unless you have a really good reason that requires you to upgrade your OS X to a later version. to be the most stable combo of OS X and Logic. The current combo you are using, has been proven, in my personal opinion, over time.
