Q: Multiple display problem in OSX 10.9.2

Thanks for sharing, it works for me

Amaga's fix solved my issue with DP display.  Thanks.

Nice of Amaga to take credit

@amaga

I also confirm that this workaround has worked for me

iMac late 2010 - ATI HD 5750, Worked like a charm!

Although I got an Error when pressing Spacebar on a file for 'Quik Look' . Problem with 'CVMCompiler Quit unexpectely'

     Anyone experience it too ?

Note regarding Amaga's patch...

The patch fixed my immediate monitor problem.  However, I've since noticed that there are some display issues.

So, before patch:  Monitor didn't work!  Nothing.

After patch:  iPhoto doesn't load.  Images start to display and then random video trash is observed.  Then iPhoto crashes.  I've observed the same with preview loading images - random trash, especially when attempting slideshow.  Then app locks up and needs to be force quit.  I've also noticed a few minor artifacting glitches in other applications.  Patches of lighter or darker grey in grey borders, etc.

Videos sometimes display trash before the video starts.  Once the video starts, it seems ok though.

amaga didn't create the patch. and, it's a hack not a patch

amaga can you please give step by step instructions of what needs to be done.I am using 10.9.2 i have tried everything else. so if you can please list your steps that would be great

What mac system do you have?  If it isn't a late 2013 Mac Pro the solution probably won't help.  Amaga was just posting files for an earlier solution that someone else posted.  If you have a system with amd graphics, post a screen shot of system profiler with extensions selected showing the amd extensions.

my solution for

works fine for me with two external displays, but I have noticed some bugs in "Preview” images. sometime are there artifacts .

Took this from another discussion but it worked!!

I called apple today 3/3/14

I got a great guy.

MacPro 2.66 Nehalem 8 core

I updated 5 days ago from 10.9.1 to 10.9.2 as soon as it was complete my 23" apple display stopped working (this is my main display).

I use an acer 22" as a 2nd display this continued to work. My hunch was that it was the update.

I tried switching the 2 montiors (no good).

I hooked up a 17" viewsonic and after 3 restarts it worked.

I tried hooking up the 23" again no good.

Then I tried a boot drive with 10.8.5 and the 23" worked again.

So it was the update.

I called Apple today 3/3/14 and got a great senior tech he had me do a "SMC"

I worked!! got my 23" back.

How to do a "SMC"

1. shut down completely

2. unhook the DVI cabel

3. unplug the computer

4 hold the power button in for 30 seconds then wait 10 sec to plug everything back  in.

SMC reset solved my issue.

http://support.apple.com/kb/ht3964

For those truly affected by this, it is a confirmed bug by apple. The bug report has now been resolved.

Sadly, I spoke too soon. It worked once after my first SMC reset but has now stopped working, even after further SMC resets!

I have reported to Apple and hope it is fixed in 10.9.3.

Sandy

Yup, installing the free Display Menu app fixed it for me with 2009 Macbook Pro and one external display. Thanks robertgeorge!