When I close the lid of my Macbook Pro (Lion), it goes to sleep, which is good: it powers down without closing my applications.

But if I just leave the computer unattended for a while without closing the lid, it attempts to shut down instead. It usually fails at this, because there's often a program such as Photoshop (which doesn't use Lion's autosave feature) blocking shutdown with a "Save as" dialog. But it does always succeed, annoyingly, in closing my browser etc. It does this even when the computer is plugged in and fully charged.

When I leave my computer unattended for 15 minutes, I want it to behave exactly as if I had closed the lid: it should go to sleep, not shut down.

How can I do this?

  • Does your laptop typically try to shutdown at a certain time of the day? If so, it could be that you have the schedule in the energy saver preference pane set to auto-shutdown your computer on a specific time interval. Check System Preferences > Energy Saver > Schedule to see if that is the problem.
    – Bryan Luby
    Apr 11, 2012 at 17:21
  • No, I've checked there; there's definitely no scheduled shutdown. Thanks anyway.
    – callum
    Apr 11, 2012 at 17:36
  • An app that doesn´t solve your problem but is somewhat related and is very useful is, Caffeine. Very nifty widget, but wont solve your bug... lightheadsw.com/caffeine Apr 11, 2012 at 19:03
  • @callum Have you taken a look in the Console for any potentially relevant messages either before or after the computer shuts down? If not, click All Messages in the left-hand pane then scroll down to the approximate time period and see whats there. Alternatively, filter the log for "shutdown" or something similar.
    – binarybob
    Apr 11, 2012 at 19:43
  • I have the same problem!
    – jlarson
    Aug 28, 2012 at 20:30

5 Answers 5


Try going to System Preferences and choosing Security & Privacy. When that application window opens, choose "General" tab and then look to the lower right corner and click on "Advanced". Uncheck "Log out after _ _ minutes of inactivity.

Not sure but this might be the cause.

Good luck


Yes, indeed, the "Log out after 60 min" had a check mark. That was the problem. I was just lucky that the OS was unable to Quit certain applications that do not use the built-in Autosave feature, but many times I found myself at the Login screen when coming back to the puter.


It could be the SMC, or a bug in the firmware. Try these two steps:

  1. Reset the SMC, see: http://support.apple.com/kb/ht3964

  2. You may need a firmware update, see: http://support.apple.com/kb/DL1474?viewlocale=en_US&locale=en_US


I know this might not be very helpful... but my guess is that you have an app or widget that has scheduled a shutdown... either that or the energy preferences but you checked that already...


Thanks for everyone's advice on this. When I asked the question I thought this auto-shutdown thing was some feature I must have accidentally enabled somewhere... But after a lot of searching, update-installing, settings-tweaking, etc, I concluded it was just some rare bug in my system.

In the end, I just re-installed OS X. That fixed it :)

  • This did the trick, thanks callum ! I upgraded to Maverick in 2014 and suddenly my mac was constantly logging off and shutting down all apps after 15min. I had that security setting enabled after the upgrade. Thanks for the tip !
    – user71316
    Feb 24, 2014 at 21:12

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