I've problems with auto-sleeping on both my MBP and iMac which are both fully updated. Nevertheless none of them is going into sleep automatically. On my MBP I've quitted all known applications from the "Activity Monitor" and from "System Perferences->Energy Saving" setting the computer to sleep after 2 min and black screen after 1 min. The screen is turning black after 1 min. but the computer never goes into sleep. It's the same situation on my iMac. I found out that, when I'm changing something inside the "Energy Saving" and close "System Preferences", I get this log message in Console: Code: 16/06/11 13.30.10 [0x0-0x4d04d].com.apple.systempreferences Couldn't find any matches. Both on my MBP and iMac. My girlfriends MBP is not having this log message and auto-sleeping is working fine on her MBP. I'm using MobileMe Sync on both my Macs. Maybe there is a conflict with some of the preferences which are in sync. I've tried to delete '/Library/Preferences/SystemConfiguration/com.apple.PowerManagement.plist' and let the System Preferences recreate the file. Not working. Other users is having the same issue: https://discussions.apple.com/thread/2403924 https://discussions.apple.com/thread/2583012 I hope someone can help me with this issue. Please tell me if you need further information.