Mountain Lion won't sleep
Since I installed Mountain Lion my computer will not sleep. This appears to be a different problem from what others are experiencing. Unlike what has been referred to on other threads, all items in my Apple menu (except Sleep) are functioning normally. However, none of the normal methods (keyboard shortcut, Apple menu, power button, Energy Saver) will put my computer to sleep. When I try to sleep the machine the only thing that happens is the cursor freezes on the screen, as though the only thing that has gone to sleep are the input devices. Tapping the spacebar unfreezes the cursor and the machine functions normally.
I have closed apps, removed peripherals, started in Safe Mode, reset PRAM, and nothing changes. Turning the computer off to save power is not a realistic option in my workflow so, for now, I'm just burning the kilowatts whether I need them or not. Any help would be appreciated.
8-core MacPro3,1
Mac Pro, OS X Mountain Lion