To set the sleep timer on Windows 10, you'll need to find and open your computer's "Power & Sleep" menu.

You can set a hibernation time for your computer in Windows 11, though you might need to enable the feature first.

My 2008 iMac won't sleep on its own, though it sleeps fine when I manually put it to sleep. Checking the Console logs, I think I've found the culprit: Code: 5/20/12 6:50:36 PM kernel FireWire (OHCI) ...