Why Does my iMac Turn Itself on at Midnight?

If your Apple computer independently starts its day in the wee hours of the morning without your involvement, you should check this setting.

I was out late the other night, and when I got home around midnight, I walked into in my home office before I headed off to bed. All was quiet. Then, I heard a sudden but familiar brief whooshing sound from the direction of my desk. I instinctively turned my head.

My iMac was booting up as if Skynet had taken over.
It was pretty freaky.

I glanced over at my Marathon clock that was positioned close to my iMac, and it eerily displayed 12:00am… on the dot.

Hmmm. That was interesting.

I took a breath and looked at my clock again. I felt that this clearly wasn’t some random moment where my iMac had decided to misbehave.

Turn Off the Schedule Mode
Was there a hidden setting in my iMac’s System Preferences that was telling my iMac to independently boot up?

I took a look, and in fact… there was. My iMac was ‘scheduled’ to turn itself on at midnight.

So, here’s what I did to turn that off:

  • Click on System Preferences
  • Click on ‘Energy Saver’
  • Click on ‘Schedule’ on the bottom right
  • Unclick ‘Start up or wake’
    (which had defaulted to 12:00am)

Problem solved.

Living with your Gremlins
I suppose the lingering question is why that scheduled action was clicked in the first place.
I certainly hadn’t done it.

It’s an issue for another time.
For now, my iMac should behave…as directed.

Thank you, HAL.