I have an iMac (late 2009 model) running Yosemite. Recently, I have set up automatic shutdown in the Energy Saver settings under System Preferences. However, if my computer goes into sleep mode before the automatic shutdown - which I have scheduled to happen after twenty minutes of inactivity - my computer will not shutdown automatically at the scheduled time.

The question: is there a way to make my iMac shutdown at the scheduled time even when it is in sleep mode, or is there no way to circumvent this and I'm better off with manual shutdowns or disabling sleep mode?

  • Prior to Mojave, when I set the computer to shut down at a certain time, it would work even if all users logged out and computer's asleep at login screen (it would wake briefly, and then shut down, if no remote users connected to this mac). Since Mojave, this feature sometimes shuts down at login screen with no users logged in. Other times, the mouse turns into busy icon, clock doesn't advance, and I have to force shut down.
    – Carsten B
    Commented Dec 9, 2018 at 23:38

4 Answers 4


You can use a third party tool like Power Manager to automate reliable shut downs.

Power Manager's power off task

By default, events will wake a sleeping Mac before being performed. Typically your Mac will be woken 15 – 30 seconds before the scheduled shut down begins. Ultimately, the wake up is performed by OS X's IOPMQueue which you can see and edit through the pmset tool.

I am the engineer behind Power Manager, so do ask if you need more details.


You could set a start up / wake right before the shutdown time. There should be enough time before sleep kicks back in to have the normal shutdown be processed.

I'd say 5 minutes of gap on a 15 minute sleep timer would be ideal.

  • Nice hack but it does not work if you are not logged in, i.e. if you have a login password.
    – Alper
    Commented Oct 20, 2021 at 11:21

Same problem, so far the only solution I've found is to buy a shutdown timer off the App Store.


The Mac will be prevented from auto shutdown if goes to sleep first. It must be fully awake.

Solution: Set the auto wake schedule 5 mins before the auto shutdown.

To shut down automatically, your Mac must be awake at the time that it's scheduled to shut down, and remain awake for at least 10 minutes past that time. If it's sleeping at the scheduled shutdown time, it continues sleeping instead of shutting down. If it's set to go to sleep after less than 15 minutes of inactivity, it might go back to sleep before it can shut down. To make sure that your Mac shuts down even when sleeping, set it to start up or wake 5 minutes before the scheduled shutdown time.

Reference: Set a startup, wake, sleep, restart, or shutdown time on your Mac (Official Apple Support)

  • This answer appears to be nearly the same as that by @bmike below
    – Alper
    Commented Oct 20, 2021 at 8:15
  • Similar I guess, but it's more structured and cited references from Apple docs which should help. The other answer sounds more based on opinion. I just didn't want to go editing someone else's answer, yet still provide others with a bit more context.
    – redfox05
    Commented Nov 18, 2021 at 17:42

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