I have problems with the Sleep function on my iMac. It will go to sleep if I tell it to go to sleep manually via the control pannel/control strip or if I press the power button on the iMac, but it won't go to sleep automatically. I've got it set so that it goes to Sleep after 30 minutes of inactivity, and not to spin down the HDD or turn the monitor off, just to go directly to sleep, yet it completely ignores this, and after about 30 mins the moniter goes off then shortly after that the HDD spins down but the actual computer doesn't go into sleep mode.

Are you running a program that requires your mac to stay active? If your computer goes to sleep, it can prevent some programs from doing what they need to do, so some programs stop your computer from going to sleep. %00

Well, I did think maybe it's something to do with that, but the only thing open is the launcher. Even so I closed it. I also made sure appletalk and file sharing was off too. But it still didn't make any difference.

Do you have the Faxstf software loaded on your machine? Even if you haven't activated it there is a part of the program (Fax Monitor) that runs in the background and that may keep your machine awake. Likewise the Time synchonizer can interfere with sleep especially if you are on cable.

Well, I don't have anything to do with FaxSTF installed, I never found a use for it. I do have the print moniter active though, would that do the same thing? I turned time sync off in any case though, and it still didn't work. I can't really turn print monitor off though, because I do print a lot mostly every other day and background printing is a must have. If that's what's causing this then I'll have to give up. Thanks for the help anyway people.