Mountain Lion can’t Wake Up from Slumber

Sleeping Mountain LionIf your primary machine is a Mac laptop and it spends a large portion of the time unplugged, you might want to hold off upgrading to Mountain Lion for a while. Mountain Lion has a problem of waking up Mac portables when it goes to hibernate mode. That is if you close the lid and leave it disconnected from the power grid for a couple of hours or so, you can’t wake it up and will need to reboot the machine.

This issue is apparent in portable Macs that comes with an SSD drive, like the MacBook Air and the Retina Display MacBook Pro. OS X update 10.8.1 did not fix this issue.

Here is the step-by-step way to test whether you have this problem:

  1. Take a Mac laptop and charge the battery until it’s full.
  2. Close the lid so that it’ll sleep.
  3. Disconnect the power brick from the unit.
  4. Wait at least two hours so that the unit automatically goes into hibernate mode.
  5. With the power brick still disconnected, open the lid and press the space bar or any other key on the keyboard. 

Logically, the unit should wake up. But apparently the screen wakes up (the Apple logo at the back lights up) but shows a black screen. At this point, the only way to access the machine is to hold the power button to reboot it.

If you’re in a hurry, here is a faster way to reproduce the issue:

  1. Charge the laptop until the battery is full.
  2. In the Terminal, type: sudo pmset hibernatemode 25
  3. Close the laptop’s lid.
  4. Wait for about a minute.
  5. Disconnect the power brick from the unit.
  6. With the power brick still disconnected, lift the laptop’s lid.
  7. Try pressing the keyboard or clicking the trackpad – the laptop won’t wake up.

I’ve tried these workarounds but none fixed the problem:

The workaround for now is to disable hibernate mode entirely. Note that your portable will still use the battery while sleeping and thus you might not want it to keep it sleeping overnight without power.

To disable hibernate mode, type this in the Terminal:

sudo pmset -a hibernatemode 0

Whereas to get back to the normal mode, type the following:

sudo pmset -a hibernatemode 3

Type ‘man pmset‘ in the Terminal for further information.

If you work for Apple, please refer to my bug report: rdar://1212084 – please, please get this fixed, pronto ^_^

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  • I am experiencing the same problem with my Late 2008 MacBook Pro since installing the 10.8.2 upgrade…

  • Charles Prince

    It’s not only Laptops that have the problem. I use a Mac Pro and it always freezes on wake up for about 45 seconds. It’s not the end of the world as apart from this problem the machine performs perfectly. But it is annoying and if I wanted to use “back to my mac” or use the machine as a server what use would it be if it fails to wake up quickly? And 10.8.2 has not fixed the issue. I have tried every fix  suggested including installing Smart Sleep. But no fix. Come on Apple get this bug sorted out. CP 

  • Pingus

    I have the MacBook Air 2012, and while I didn’t have this issue in 10.8.0 and 10.8.1, I now have the issue in 10.8.2 🙁

  • daretothink

    This is the bane of my life at the moment. Sometime my MBP 2010 decides it wants to go to sleep and wake up perfectly and then other times it won’t wake up for ages, including today where I’ve pressing the power button on/off for around 3 hours in an attempt to get it to wake up! Finally it did but now I’ve set the hibernate mode to disabled, which is not ideal

  • The same problem here too… Macbook Pro 2011 10.8.2 !
    Where is Apple, dude?!

  • Does everyone who installed the Mountain Lion have the same problem?

  • Massimiliano Colla

     I do. I have a MBP late 2012 10.8.2

  • Mubashir Rehman

    yes, i have macbook with ML , and goes into sleep mode , i am not able to do anything . 

  • Yep. mbp 2010 10.8.2

  • yep.
    MBPRO late 2011,10.8.2

  • what is you bug report status?