Some MacBook, MacBook Pro or MacBook Air won't wake up from sleep. My MacBook Pro was one of them. I have been googling for two days, and I learnt different ways to fix the problem. Not all the MacBooks can be fixed by the same one solution. Here I collect five common ways to fix the waking up problem together (trying to save time for others). If your MacBook doesn't wake up from sleep, you may try and see which solution works for yours. If any solution works, you may leave a message including your MacBook model and the solution. It may help the others.
I learnt this solution from AJ's post. AJ said even in a single boot MacBook, a startup disk is rarely selected, and sometimes, this may stop MacBooks from waking up from sleep. Here is how to fix it:
SMC stands for Mac's System Management Controller. Many strange behaviors are related to disorder SMC setting. By resetting SMC, you may fix sleep problem of your MacBook. Here is how to reset SMC of your MacBook.
Reset SMC of a MacBook, MacBook Air, MacBook Pro with an internal battery you should not remove on your own:
Reset SMC of a MacBook, MacBook Air, MacBook Pro with an battery you can remove:
Safe Sleep(or hibernatemode) was introduced in 2005. This Feature writes the content of MacBook's RAM onto the hard disk before you put the MacBook to sleep. Normally, when Macbook wake up, it does not need to read the hard disk for the RAM's content, because RAM is not turned off when Mac is sleeping. Safe Sleep is there just in case that the MacBook is short of power and turn itself off or you remove/change the battery. And that is why it is call SAFE sleep.
Sometimes, Safe sleep may cause MacBook can not wake up from sleep. You may try to turn it off, here is how:
This very solution fix my MacBook Pro. If it doesn't fix your problem, you can restore the safe sleep feature with running following command line in Terminal:
sudo pmset hibernatemode 3
If you have installed a second hard drive (or SSD) on your MacBook or MacBook Pro, and have waking up problem of the mac, you may try to install Mac OS X system on the other disk of the book.
I have removed my optical drive of my MacBook Pro, and installed a second hard drive. When I installed Lion on the second hard drive, my MacBook Pro could not wake up from sleep. Then I tried installing Lion on the original hard drive, the MacBook Pro did not have the problem.
Backup all you data, and try re-install the Mac OS X system. It always will be a solution to Mac problem.
I hope some solution above will work for your MacBook. If not, maybe you just have a broken Mac, it is time call Apple.