I posted a thread very long ago and did i a ton of research but still never find the solution. The problem is that my Unibody MBP fails to sleep with the lid open, even if I set the sleep time to 1 min and leave the machine idle for many many nights. I have nothing connected to my machine and I make sure that the machine is really idle by closing all the program. I even try creating new user and safe boot to check if the problem is caused by the third-party apps, but still my machine won't sleep in safe boot or the new user accounts I created. Already reset the pram/smc and the efi?? thingy. Nothing work. I used to have the sleep related issue (won't wake up from sleep) when i first got my machine, but it was fixed by the smc/efi update from apple. However, this not sleeping when idle that's bugging me seems to be caused by the 10.5.6 update. I would want to redo a clean install of leopard, but I don't know how, and worse, I don't have a drive to back up all my data. So, reinstalling is not a viable solution.