Ask Different is a question and answer site for power users of Apple hardware and software. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm running Snow Leopard 10.6.8. I leave my machine for an hour. When I return the machine is asleep and all the applications have been shut down. It is almost as if it has spontaneously restarted.

Any ideas what could be causing this?

share|improve this question

I'm not sure what is causing it, but it sounds like a hardware issue, or that the power outlet the machine is plugged into may be faulty.

You can try going to the Energy Saver preference pane and unchecking Start up automatically after a power failure. If the computer really is shutting down and restarting this may help you find out.

If it is shutting down, it may be:

  • Faulty power supply
  • Faulty power outlet or another electronic device complicating power in that outlet
  • Overheating
share|improve this answer
I don't see this option on Snow Leopard. – Eric Brotto Jun 20 '12 at 11:27

If you are running Lion, you may be seeing the effects of Lion's auto kill feature. This feature automatically quits any applications that are open if they haven't been used in awhile. Try disabling it as such by typing this in Terminal:

defaults write -g NSDisableAutomaticTermination -bool yes

To turn it back on:

defaults write -g NSDisableAutomaticTermination -bool no

From this answer.

share|improve this answer
Could this be on Snow Leopard too? – Eric Brotto May 21 '12 at 15:43
@EricBrotto No. Snow Leopard did not have auto kill. – daviesgeek May 21 '12 at 15:48

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.