Q: 10.9.3 kills third monitor

Care to share? Dropbox? Link?

Yes, can someone please share 10.9.4

I can share some data points here.

I have a team of 6 guys.  We all had older 12-core mac pros with various graphics cards (mostly the old ATI cards that could drive three monitors although we also had a couple with aftermarket Nvidia cards).  Three of us were running 3 x 30" monitors (using DVI or MDP->DualLinkDVI).  One was running 2 x 30" (again with MDP->DualLinkDVI).  Two were running Apple 27" monitors.

None of those old Mac Pros were affected by the 10.9.3 upgrade.  All kept humming along with 1, 2 or 3 monitors.

Yesterday, we received 6 brand new Mac Pros (2013).  One of us upgraded to dual 4k monitors using MDP->DP cables... that's working fine.  Two of us were still wanting to use 3 x 30" using MDP->DualLinkDVI adapters... but only _two_ monitors will work that way!  The guy using 2 x 30" monitors via MDP->DualLinkDVI is just fine... and the other two using single 27" Apple monitors are fine.

To summarize: we cannot run more than two 30" monitors from MDP->DualLinkDVI adaptors on the new Mac Pros.

However, we noticed that one of the two guys affected by this bug has a newer set of monitors that _do_ have DisplayPort on them.  So we jacked his 3 x 30" monitors into his new Mac Pro using MDP->DP cables... and it works perfectly!

All in all... we paid over $45k for these machines... and I'm surprised to see this much trouble with trying to use monitors with them.  One guy is currently sitting in front of 2 working monitors and 1 blank one.  I haven't contacted Apple yet... but I am going to do that soon.

I hope 10.9.4 lands soon...

Hey, what happened to the links to 10.9.4 that were posted and helped others yesterday?

I think they pulled the 10.9.4 program to start a 10.10.0 program.

apple removed my posting.  just use google to find it. and please remember to report the problem to apple via http://bugreport.apple.com

Same here, got an email from Apple noting that the beta was a Developer only download so the link was unappropreate.

Apple is not a monolith. The rules on this forum preclude postings about stuff covered by Apple Non-Disclosure Agreements, so that is why those things get pulled.

You still need to press on the parts of Apple that make decisions about how to recover from Updates that cause problems for Users. The broader testing (by opening the late-stage Beta to "regular folks") they did this time around was NOT a solution. I recommend product feedback as well:

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

All valid points.  For me (your mileage may/will vary) TImemachine worked as a roll-back mechanism.  I will in the future be much more diligent to run a manual TM backup before installing an update. I got somewhat lucky in that I had not made any significant changes since the last backup when I installed 10.9.3. 

I was therefore able to use the recovery partition boot to pull the last 10.9.2-based TM backup back to my hard-drive. That roll-back was almost error-free (Google Drive gets confused when you do this, and a few web sites and applications need to re-confirm login/security settings).

For me this was a 3 hour+ process, I hope I won't need it too often.  I know not everyones setup allows individual TM backups, but where you can set up up, I recommend it.

i also got this answer. But where can we see the content of #16796953?

tried the new beta 10.9.4 "13E16" yesterday and the problem seems to got worse again. needed to reboot several times to get the third monitor running again. i can definetly say that 13E16 is no improvement over 10.9.4 beta built "13E10" because it worked also not flawless with the third monitor! for example: when my monitors go to energy save mode, very often, i got an error on the third monitor that the resolution is out of range! this also happend often on system startup. with the new beta 10.9.4 13E16, it has not been fixed yet! the problem with multi monitor support is still there!

i've just submited a new bug report via bugreport.apple.com. i suggest everyone with this problem do the same. the more submits, the sooner we get a real fix, i suppose.

Beta 10.10 has fixed the problem on my computer, yay!

HACKINTOSH! 10.9.3

This worked! Thanks so much for this!

EVGA GTX 780 Graphics card.

I am using 3 LG 27MP35HQ Monitors. All HDMI inputs.

Connections - Card to Monitor

1 DVI to HDMI

1 HDMI to HDMI

1 DP to HDMI

All running 1080p

THANKS AGAIN SO MUCH FOR THIS QUICK FIX!!!!!

MacDaddyPro

Although this fixed the 3rd monitor problem I now have the other problem. Preview crashes.