MacBook Air fails to "wake"

Question

I have a 2014 MacBook Air running 10.9.5 with 1.4 GHz Intel i5, 4GB 1600 MHz DDR3.
Have only noticed today that when I try to wake it from sleep mode, I get a black screen and only my cursor- and nothing else. Not even my screen saver, so I have to press the power button (the only key that seems to function). It runs fine in all other respects, and the only updates in the last month are the security update (2015- 002) and the update to Safari (which I don't use anyway).
Not sure what could be causing this- and if anyone's got a solution that'd be great.

Answer 1

Hi flowerbedgrl
Hope you are well.
So, I'm guessing you've noticed this multiple times today (it wasn't just a once-off)? I'm also assuming you've checked your Energy Saver settings etc.
You could try doing this:
Shut down the computer
Unplug the power cable
Wait about 15 seconds, and reconnect power cable
Restart while holding down Command and S (keep these keys pressed until you see a black screen with white text).
When the text stops, the bottom line should read: root#
Type in the following lines (taking careful note of where the spaces are), one by one, pressing the return key after each line:
mount -uw /
cd /Library/Preferences                            
mv com.apple.loginwindow.plist oldlogin
reboot
    7. Your Mac will reboot.
If you find that your Mac still does the 'black screen' thing, wait about 10 seconds and try clicking around with your cursor to determine if it now wakes up or not.
Hope this helps.
Joe.