OSX Black Screen no Login screen but with working cursor on boot [fixed]

I'm just posting this, to maybe help others who get the same problem.

I had an OSX 10.10.2 update on my 2011 Macbook Air, and left the laptop open last night.  This put it in Hibernation mode which breaks the auto-installation, so when I tried to use the laptop this morning, it booted to the Apple logo, but then the screen went totally black without the option to login.  The cursor was still live though.

The fix below will let you login again.  It will only work in the above scenario, if its your backlight broken or something else keep searching :)

Before the below fix I tried:

  1. Pressing the increase brightness buttons (duh)
  2. Restarting in safe mode (doesn't complete login)
  3. Resetting SMC and PRAM (pusing CTRL+OPTION+POWER+other buttons on powerup - see here: https://discussions.apple.com/docs/DOC-3603 )
  4. Letting it boot, waiting, then pushing first letter of your username, pushing enter and typing in password (the most popular fix on the web)

But finally, the solution was found at this forum called Jamfnation via some Google-wu:

  1. Perform a PRAM reset ( Cmd+Option+P+R ) on boot – let chime 3 times and let go
  2. Boot to Single User Mode (hold Command+S immediately after powering on)
  3. Verify and Mount the Drives - Once in Single user mod, run the following commands:
  4. /sbin/fsck -fy
  5. /sbin/mount -uw /
  6. After the disk has mounted in step 5, run the following commands:
  7. rm -f /Library/Preferences/com.apple.loginwindow.plist
  8. rm -f /var/db/.AppleUpgrade
  9. After deleting the files, restart.

Hope it helps if you get this far.