Sometimes my mac pro is unable to successfully sleep. (2009 model) Normal behavior is that if no flagged programs are open, I it will automatically sleep after a period of inactivity. I can hear the "click" of my map pro and the fans (and hard drives) powering down when it does this. The light above the power button will slowly fade off and on while it is asleep (as opposed to the solid unwavering light when it is on normally). Of course, I can do this manually if I want via the apple menu. However, lately it wont do this. It will stay powered on indefinitely unless I tell it to manually, which still doesnt really work. It causes my monitor to stop displaying anything as though it were sleeping normally, however the computer is clearly still on: light above power button is still on, fans dont power down, no click, response right away when I shake the mouse. Usually this seems to happen when I have logic open for an extended period of time (this is a program that is flagged to not allow the computer to sleep while it is open), and then close logic. Even though the program is no longer open, and no other programs that would cause anything of the sort are open, it simply wont sleep until I shut it down. When I boot it up again, it usually performs normally, but now it simply wont sleep regardless of whether anything is open. No applications open and it still wont sleep. What is wrong with it? Edit: okay, I might slightly wrong. While I have found that when it starts doing this, it can be left alone for hours without ever entering sleep automatically, but I just tested it manually again, and using a timer, I have determined that it does, in fact, go to sleep, but only after a solid 22 or so seconds of waiting. It normally happens within 2-3 seconds. Any ideas?