Hi, I know there are other threads but it does seem like a lot of people are having this issue. Hopefully Apple are reading and they provide a fix. I have a 27inch iMac with the 3.2 i3 processor and 4G of RAM. I have a wired network connection to a 1TB Timecapsule and on the same network is an AppleTV2, also wired. I looked at other threads on this subject and a lot of people to say to switch off sharing etc. I have done this and have no sharing at all. Other than home sharing so my AppleTV can play my music and videos. I had the exact same configuration under Snow Leopard and my computer would go to sleep. (Except of course during a backup or using AppleTV). Now under Lion, no sleep at all! I can't even tell it to sleep by pushing the power button or by selecting sleep in the Apple menu. The screen goes black but the fans and HD are still whirring. I would like my computer to sleep! Thanks.