Second display problem with 10.9.4

HDMI to HDMI tested. Makes no difference as suspected.

One other interesting thing:

External monitor and macbook screen both show the desktop although I cannot move my mouse pointer from external monitor to macbook monitor. When I pull the thunderbolt cable out of the Macbook *both* screens go black and there seems to be no return from this... a reboot is required. What should of course happen and has been happening up to now is that all open apps etc on the external merge with the apps that are open on the macbook screen (as the external has been disconnected). Help. :-)

You should really file a bug at https://bugreport.apple.com/ -- the more data they have, theoretically the better they might be able to fix their display issues.

(I'm ignorant on that model of the MB Pro, but the tech specs list two graphics chipsets (the on board Intel HD 4000, and the NVIDIA GT 650M) -- is one driving the laptop's screen and the other is devoted to whatever external displays there may be? )

When both screens go black forcing you to reboot, have you tried instead (if you have another machine on the same network) SSH'ing into your laptop and killing the WindowServer process? It's plausible that kicking it into restarting itself might rescue the display in the new configuration so you needn't reboot.

Well, you are not alone!

Someone at Apple is doing crazy things about the graphic drivers.

Actually I have big problems using more than one monitor on the new Mac Pro 2013 since 10.9.4

They say they made some changes in the drivers to get better 4K functionality in newer Macs.

Unfortunately the changes didnt just messed the Mac Pro up, they messed the whole system up...

Just for fun I tried to get the monitors working with the 10.10 Yosemite Beta. And it worked!!

In the End you probably have to wait until Yosemite is available. :/

I will file a bug report.. thanks

Interesting about Yosemite... I can survive on a single screen for a while no problems.. I'm just at that stage where I'm hoping I haven't messed something now in attempt to fix it (e.g. the kext fix).. don't think I have but you never know.

Did you overwrite your current install with the Yosemite Beta or how did you test it out? I won't be doing that anyhow... I find it takes courage to install the General Availability release OS these days ;-)

Users of Yosemite betas have to sign a non disclosure agreement that bars them from discussing it publicly. It is not fair to them to ask questions about it of them.

Good for you for keeping us right with the rules. Can I send a few points your way or somehow help you level up? To be absolutely honest I wasn't aware there was an NDA in place for Yosemite betas as I'm usually only on this forum only when the s*** hits the fan!! At all other times I'm working on a single display or out having fun :-)

Hi I lost my second monitor when I upgraded to 10.9.4 from 10.9.2 a few months ago

I would like to upgrade to Max OS X 10.9.4 As I now see a new driver

Im still on OS X 10.9.2 (13C1021) which works and I can see two monitors now

ive posted on apple forum and bug report just now.

APple please help!

I would just like to add this link I saved a while ago when I tried to upgrade to OSX 10.9.3

I thought Apple would have fixed the problem by now.

I've been a user of Apple products since Mac Plus and Im not happy right now.

Please see

http://preview.tinyurl.com/oh48t8o

I had the same issue so I called and paid for apple care… was an awesome experience, thought I would share the value:

After all of the typical troubleshooting steps failed to resolve anything... he walked me through the following:

restart in safe mode:

-shut down your laptop.

- press and hold shift key, press power key, keep holding the shift key until the apple and spinning gear are on the screen, then release the shift key.

Login.

Finder, GO, Computer, MacintoshHD/Library/Preferences: drag anything with “windowserver” filename to trash.

Finder, GO - hold down the option key (you will notice the list changes to include Library), Library/Preferences/ByHost: drag anything with “windowserver” filename to trash.

Empty Trash (if anything left in trash, then go Finder, Secure Empty Trash)

Then restart.

This worked for me. Good luck.

altoronto's solution does NOT work for me. I restarted in safe mode, had a com.apple.windowserver... file in both locations, deleted both, cleared trash, one of the windowserver files was still there, secure cleaned trash, restarted, same problem still there.

My specs:

MacBook Pro, 15-inch, Mid 2010

OS X 10.9.4

2.4 GHz i5

4 GB DDR3

The altoronto method worked for me, but I had to reinstall a bunch of Exchange settings afterwards, not a big deal.

Cheers!

The altoronto fix worked for me as well.

The altoronto fix unbelievably also worked for me. You can see the strangeness I was experiencing in posts above and I'm on a Macbook Pro Retina Mid-2012 with a Dell U2713h monitor. Thank you very much! I can hardly remember how to work with two monitors its been that long :-)

Side effects: Not much, 1 1password firefox extension didn't work in my browser until I started the app again first, but after starting the app it works fine. Haven't seen anything else so far.

I have two 30" apple CD wired to my Mac Pro 2012, and the graphic card is a flushed geforce gtx 680 4GB.

My displays have been working fine until the 10.9.3 upgrade. It all started then. Only one display worked after updating.

It seemed like many had the same problem, and I found a fix that has been working ever since - until 10.9.5.

I have been installing geforce and nvda kext from 10.9.2 after the 10.9.3 update and I had to do it also after the 10.9.4 update.

It solved the problem, and both displays started working again.

I installed the 10.9.5 update in good faith, and really believed that apple had fixed my problem in this update, but it happened once more.

The problem is, that this time, the mac can not boot after installing the 10.9.2 kext. After the apple logo and the spinning wheel beneath the apple logo stops and it is supposed to change to the login window, the machine restarts. Both displays are now working, but it does not help me, since I can not boot. When booting in to safe modus with the 10.9.2 kexts, both displays works, but I have to go back to the 10.9.5 kexts again, to get the machine to boot properly again.

This is a big problem! I am a video editor and colour grader, and I do not want to wait to the next upgrade or 10.10. I do also not want to use a day or two to reinstall everything again to try to get back to 10.9.2.

Are there any solutions? Someone who has had and managed to fix the problem?

Mac Pro, OS X Mavericks (10.9.5), Mac Pro 2012