External monitor stopped working after 10.9.2 update installation

using late 2012 macbook pro, non retina display. After updating to 10.9.2, my Dell 288WP external monitor no longer works with the machine. I've tried resetting PRAM, repairing preferences. It DOES work in safe mode, but how does that help me?

oh, I've tried different DVI adapters, different VGA cords and even different monitors.

Thank you middaparka, I did what you suggested and disabled DisplayPort 1.2 support on my Dell monitor and my external monitor is once again recognised & working. Much appreciated.

As you suggest in this thread: https://discussions.apple.com/thread/5939590?start=15 - this indicates that the problem is a bug in 10.9.2 wrt DisplayPort 1.2

I found this elaborate discussion on the topic.

It seems there are possible solutions.

http://embdev.net/topic/284710

To check if you have the specific problem look in your configurations under About this mac, system..

Display drivers.

If it says Television-Yes

than you do have the problem described.

Re: Dell U2713H on Mac: forcing RGB mode instead of YCbCr

Yes. By disabling display port 1.2 support can solve this issue. I'm using a dell U2414H.

Thanks for that. Follwed advice and "Disabled" Display Port 1.2 Support and the issue seems to have been resolved.

I am using a Dell U2913WM monitor. http://www.dell.com/ed/business/p/dell-u2913wm/pd

Same problem here with the same Kogan monitor after the same OS update. I too use this second screen for my day to day work. Would be great if there can be a solution provided soon.

adelaidian, you're only going to get a solution if you ask for it. 10.9.2 looks to be buggy as a result of releasing too early in a panic caused by the SSL issue. Apple probably has a lot of bug fixing to do.

They don't bother reading here - if you want this bug fixed, then you'll need to ask: https://bugreport.apple.com

I have had this issue for more than a month with the 10.9.2 beta and released versions. Bug reports filed and got no traction. My problem is on a Late 2013 Mac Pro with two Crossover q27 displays.

I am able to get it working with the previously working drivers (ATI) :

AMD7000Controller.kext

AMDFramebuffer.kext

AMDRadeonX4000.kext

AMDRadeonX4000GLDriver.bundle

AMDSupport.kext

Thanks for this, I was having the same problem with my AOC Q2963PM after the update and was able to turn off Displayport 1.2 (back to 1.1a setting) on its OSD and get my display working again.

Note for AOC (and possibly other monitor) users: only by putting another input source into the monitor that the monitor can display, will the monitor let you get into the OSD menu in order to set up this option. Frustrating and terrible catch-22 if you didn't have another input source handy.

Or report it to

http://www.apple.com/feedback/macosx.html

if you are not a registered Apple developer...

Grrr

Where did you get the previous working drivers? from a backup? Echoing the OP, Im having a similar problem my external display (27 in Shimian, mini dp to powered dual dvi) no longer working with my MBP (early 2011) after the 10.9.2 update. When I plug it in both the external display and MBP display go blank and I have to power down and back up in order to get this display back on my MBP...it is killing me! I've reported this to Apple as well.

Try unplugging your external monitor from your power source, restart your Mac and when you get back to your desktop and your Mac starts blinking plug in your monitor back in. It's a pain in the *** doing it every time but it works for me.

-Mavericks 10.9.2

-HP w2228h external monitor

-Mini Displayport to HDMI cable