So, not since the days of Mac OS 9 have I set a sleep period in the Energy Saver prefs pane and actually had it work, is Apple ever going to fix this do you think? Basically, I set a time for the Mac to sleep after, the screen goes black but the Mac doesn't sleep. This is the same for 6 different Macs I use, and the problem has always been there since 10.0 for me, whether I've clean installed or upgraded. Even brand new Macs don't do it out of the box for me. Crazy!