I've noticed since I got my new MacBook Pro (6,2, 10.6.7) that when the battery runs out while the computer is sleeping, Safe Sleep doesn't kick in upon restart. It used to be that with my old MacBook Pro (3,1, 10.5.8), when the battery ran out while the computer was sleeping, I would get the progress bar under the Apple logo during EFI boot. On my new computer, when the battery dies, the computer dies.

When I put the computer to sleep, there is the delay before the breathing light comes on (as it's writing the contents of memory to disk for Safe Sleep), but it seems to make absolutely no difference when I turn the computer on. Any ideas?

Edit: As suggested by @Chris_O:

perfora:~ tyson$ pmset -g | grep hibernate
 hibernatefile  /var/vm/sleepimage
 hibernatemode  3

You can check if safe sleep is enabled with the following command in Terminal:

pmset -g | grep hibernate

If safe sleep is enabled it should return: hibernatemode 3 or if not enabled it will return hibernatemode 0

If it returns hibernatemode 0 you can enable it by typing:

sudo pmset -a hibernatemode 3

  • See my edit; hibernatemode is 3. Thanks for the suggestion! – squircle Apr 26 '11 at 2:43

You should check out low battery saver. It's an app that makes sure your Mac sleeps before the battery completely runs out and let's you set a warning to alert you that the computer is about to sleep (lowbatterysaver.com/appstore.html) It won't fix your battery problems but at least you won't lose your work, have to restart your computer etc.

  • That's not even related to the problem. – squircle Feb 16 '12 at 0:34
  • Please read the entire question before posting an answer. – zeel Nov 6 '12 at 4:12

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