Not sure what's going on... I have "wake from network access turned off", but sometimes the iMac will wake itself up, usually shortly after going into sleep mode. One thing I previously troubleshot was my USB connected printer. If I turned that off while the iMac was in sleep mode, it would wake the machine up. I don't do that anymore. Any ideas as to what would make the machine wake up shortly after going to sleep? Nightmares of Windows 8 taking over the world? Insomnia? Anything is possible!