SOLUTION: Display goes dead after Mac OS update
 

When I updated my Mac OS my display went dark and refused to work.

I spent quite a while without my third monitor. Mainly because I was not finding anything useful online.

I finally found something that seems ridiculous, but works.

It seems that some of the Mac OS updates mess up the Disk Permissions, sometimes!

If, when you update your OS, your screen stops working try the following:

1. Install the latest drivers.
2. Run this from the command line: sudo diskutil repairPermissions /
3. Reboot.

Here are some article I found on what repairPermissions is and does:

• http://www.macworld.com/article/1052...rmissions.html
• http://howto.cnet.com/8301-11310_39-...d-up-your-mac/
• http://mac.tutsplus.com/tutorials/ti...-mac-problems/

Thanks man, this saved my day.

I didn't get the second monitor working until I fixed the permissions. Now everything's fine again.