Answer to: Mac Pro won't wake up from sleep with Mountain LionI found the simple fix! my Mac Pro is from mid 2008. After I recently installed Mountain Lion when it goes to sleep it often won't wake up. I would have to force shutdown and restart. I didn't find any satisfactory solutions online. What I discovered though was to go to System Preferences, then Energy Saver and click off all checked boxes. My computer wakes up every time now. Problem solved. That easy!!!