MB can't wake up from sleep anymore

Question

Hi,
Since 1 month or so my laptop is not able to wake up from sleep when I open the lid. The screen just stays black and I have to do a hard reset in order to use the computer again. Called apple help center and they made me repair permissions on the disk utility as well as re-installing mavericks, but it didn't change anything. This problem occurs maybe 4 or 5 times out of 10. Before the last update of mavericks I didn't had this problem.
Do you have any idea what could be going on ?
Thanks !

Answer 1

Step 1
Take all the applicable steps in this support article. That's the starting point for any further efforts to solve the problem. Please read the whole article carefully (some of it is hidden by disclosure triangles) and don't skip any of the steps, including the ones under the heading "Additional troubleshooting." If you don't understand any of the steps, ask for guidance.
Step 2
If you're running OS X 10.8.5 or earlier, from the menu bar select
           ▹ System Preferences... ▹ Accessibility
If the checkbox at the bottom marked
          Enable access for assistive devices
is checked, uncheck it and test.
If you're running OS X 10.9 or later, select
           ▹ System Preferences... ▹ Security & Privacy ▹ Privacy ▹ Accessibility
If any applications are listed on the right and have a checked box next to them, uncheck all the boxes and test. You may first have to click the padlock icon in the lower left corner of the window and authenticate as an administrator to unlock the settings.
Step 3
This step must be taken as an administrator. If you have only one user account, you are the administrator.
Launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Console in the icon grid.
In the Console window, look under the heading DIAGNOSTIC AND USAGE INFORMATION on the left for Diagnostic and Usage Messages. If you don't see that heading, select
          View ▹ Show Log List
from the menu bar. In the search box in the window's toolbar, enter "powerd" (without the quotes.)
You may see one or more lines like this:
com.apple.message.signature: Platform Failure
If you do see that, and you did everything in Step 1, then you're dealing with an internal hardware fault. Make a "Genius" appointment at an Apple Store, or go to another authorized service provider.