Q: Mac Pro keeps logging out since El Capitan

Same thing for me on 2009 mac pro with 3 graphics cards and 3x30" apple displays. If I knock it down to a single display it's fine on any graphics card. Not happy!

Send Apple feedback. They won't answer, but at least will know there is a problem. If enough people send feedback, it may get the problem solved sooner.

Feedback

Or you can use your Apple ID to register with this site and go the Apple BugReporter. Supposedly you will get an answer if you submit feedback.

Feedback via Apple Developer

Thats a good idea for everyone- I just used the bug reporting tool on the developer page to submit a bug.  These older Mac Pro's are widely used in my field (software development) and most coders I know use as many monitors as they can.

Update- A full day of use on the AMD HD6870 running 3 HP ZR2740 monitors at 2560x1440 - No logouts- no lockups.  The GT120's couldn't get through 10 minutes of computing without logging out.

I have been running hours now with two monitors connected to my GT 120 and nothing to  my 5770 (PC-not Mac flashed) with no problems

I also was being constantly logged out, and thank goodness was able to read this thread before I got logged out again. I also have a 2009 Mac Pro with a GT120 and a flashed GTX 680 (used for Cuda Cores for 3D) both hooked up to one monitor. After I read this thread I removed my GT120, and the problems have stopped. Kind of amazing that and Apple OEM card would cause conflicts with their own operating system.

I hope they release a patch soon, this is lame.

2009 Mac Pro with two GT120 and 4 monitors - system logs off within a few seconds of any UI intensive operation

Filed bug report: 22946290

Having spent some more time experimenting, it seems to me that the problem arises not from multiple monitors but from multiple video cards. When I run two monitors (both Apple Cinema Display 23") off one card (NVIDIA GeForce 120 GT) the system seems stable, albeit the user interface on the second monitor is sometimes ever so slight laggy. However, as soon as a screen is connected to my second video card, the system becomes unstable.

Can I ask: does this problem seem only to affect the GeForce 120 GT card or are all types of cards affected? I ask because my simple solution was to spring for upgrade video cards.

HI, yes, the problem is with multiple video cards.   WindowServer crashes and is causing the issue.  Since the GT120 was standard in this version of the Mac, not too many people have more than 1 of another type of video card in their machine.  At least I have not seen anyone post anything about more than one non GT120 card.

Regards, Brian

HI, yes, the problem is with multiple video cards.   WindowServer crashes and is causing the issue.  Since the GT120 was standard in this version of the Mac, not too many people have more than 1 of another type of video card in their machine.  At least I have not seen anyone post anything about more than one non GT120 card.

Regards, Brian

But you have to have monitors connected to more than one card. I have a GT 120 and a PC 5770. With one monitor connected to each card there is problem. With both monitors connected to my GT 120 no problem.

The 5770 is still install.

Also, presently both GPUs are doing computations.

No problems

jjrodger wrote:

 

Having spent some more time experimenting, it seems to me that the problem arises not from multiple monitors but from multiple video cards. When I run two monitors (both Apple Cinema Display 23") off one card (NVIDIA GeForce 120 GT) the system seems stable, albeit the user interface on the second monitor is sometimes ever so slight laggy. However, as soon as a screen is connected to my second video card, the system becomes unstable.

 

Can I ask: does this problem seem only to affect the GeForce 120 GT card or are all types of cards affected? I ask because my simple solution was to spring for upgrade video cards.

same issue for me.

mac pro 2008

2 video cards: Nvidia GeForce 8800GT and ATI Radeon HD5770

4 monitors 22"

OS X El Capitan

regards

Hate to sound like a broken record here, but unfortunately this is also happening to me.  Come on Apple!

Mac Pro (Early 2009)

Processor 2 x 2.26 GHz Quad-Core Intel Xeon

16GB Memory

2 x NVIDIA GeForce GT 120 512 MB

2 monitors

Unplugging one monitor has confirmed that logout issue does not happen.

Could this be caused by this new "Metal" thing? Is there a way to disable it for now??

Same issue here.  Been happening since the betas as well.  My system is as follows...

Mac Pro (Early 2009) Model: 4,1 - 2.66 GHz Quad-Core Intel Xeon - 8 GB 1066 MHz DDR3 - 2 NVIDIA GeForce GT 120 512 MB cards installed. Two 20" Cinema displays and one 20WSX Cintiq. 

2 Monitors work fine as long as they are attached to the same card.  Once you attach to two separate graphics card then constant frequent crash to login screen.  Obviously 3 monitors won't work as with the GT 120's theres only 2 inputs per card.  In addition I tried installing new updated web drivers provided by NVIDIA.  No help.

Ironic thing is I tried sending a feedback bug reports but the system kept crashing before I could send off.