MBP won’t wake up from sleep I have this strange problem with my early-2011 MacBook Pro, running on OS X 10.6.8: as of a month or so, sometimes it does’t wake up from sleep unless I press the power button for a longer period (5-10 seconds). However, when I do that, it starts waking from hibernation (the grey screen with the progress bar appears) and then it restarts. Usually the battery shows half full, so theoretically it shouldn’t go into hibernation.

Anybody else running into this problem? How did you solved it? (I should mention that upgrading to Lion or Mountain Lion is not an option, so please don’t suggest that.)
It sounds like your battery is in bad shape. Your MBP goes to sleep and when it runs out of juice it simply dies.

If that's not the case - meaning the battery got's juice after a hard reset (holding power button for 5+ secs) without hanging to power supply then: First check if there are any Firmware updates. Then try the following:

Open up a Terminal in /Applications/Utilities/Terminal and to disable hibernation type:

sudo pmset -a hibernatemode 0

then remove any trace of previous hibernations:

rm /private/var/vm/sleepimage

After that reset the SMC aka System Management Controller:

MBP with removable battery:


Shut down the computer.
Disconnect the power adapter 
Remove the battery.
Press and hold the power for at least for 5 seconds.
Release the power button.
Reconnect the battery 
Turn on the computer.


MBP with non removable battery:


Shut down the computer.
Plug in the MagSafe power adapter if not already connected.
Press the Shift-Control-Option left side keys and the power button at the same time.
Release all the keys and the power button at the same time.
Turn on the computer.  


The LED on the MagSafe may change states - if so it means your SMC reset was successfull. To enable Safe Sleep again open Terminal and sudo pmset -a hibernatemode 3. Hope that help's.

Update
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