Q: Mac Pro keeps logging out since El Capitan

Exact same thing for me but crash was within 1 minute.  This is a major flaw in El Capitan.  No other explanation.  Have to go back to Yosemite.  Tied that on Recovery-Surprise- No recovery to Yosemite seems possible using R!  Have to do a new install of Yosemite.

Just to pile on here: I'm having the same problem.

I have an early 2009 Mac Pro, single-socket. I have upgraded to a single hexcore Xeon and 5,1 firmware. I have the original GT120 in the first slot, a Quadro FX570 in the other x16 slot, and an identical FX570 in one of the slower slots. I normally drive four monitors, three 2560x1440 panels and one 1920x1200 panel (the latter from the quadro in the x4 slot).

Right after upgrading to 10.11 I get the crashes back to the login screen seconds after the desktop loads. I can't really do anything. I've confirmed that dropping to a single card (with one or two monitors) makes it work again.

I haven't tried either of the two proposed solutions because I can't possibly work with the danger of being logged out in the middle of something. I'm heavily dependent on all four displays, but stability is important. So, I'm going to wait for apple to do something, or roll back to 10.10 if I have to.

I filed a bug and included my system report. As a software developer, I definitely encourage everyone to make sure they've opened a bug for this!

I am right now booting from my backup boot drive with OS 10.9.5 and preparing no nuke/pave/clone the drive that has 10.11 on it. Between this and the pop mail headaches, I have decided that I'd prefer to go back to what was working. I will probably leave this 2008 Mac Pro on 10.9.5 until the Adobe suite won't work on it, & then I'll probably upgrade to a new machine.

this has been a frustrating couple of days.

Exact same thing for me but crash was within 1 minute.  This is a major flaw in El Capitan.  No other explanation.  Have to go back to Yosemite.  Tried that with Recovery-Surprise- No recovery to Yosemite seems possible using R!  Have to do a new install of Yosemite.  Re-installing Yosemite.  Major issue with that also.  Install will only find TM with same version of Yosemite (March!). Had to wipe disk for install. EC prevents Yosemite recovery install.  Apple has now wasted hours of my time.  Will have to manually transfer documents and latest apps.  Dropbox to rescue since TM restore to last Yosemite backup not available.  I'd really have to vote against any bonuses for Apple management who suckered us into this "upgrade" that trashed our machines.  It is obvious that they did not spend time and money determining compatibility with multiple graphics cards.  Nvidia's  GT 120 driver updates are non-functioning.  Have to wipe the install disk to wipe the graphics update since updated drivers do not work with Yosemite. Major PIA caused by these over-paid executives at Apple.  What an arrogant and cynical lot to dump this on us.

Add another one to the list. Mac Pro early 2009 with Geforce GT120 and Radeon HD5770. Constant logouts and two kernel panics so far.

Tried nVIDIA drivers and default ones with same result.

I updated to El Capitan at the same time I reinstalled the GT120 and the second monitor, so until I found this thread I was pretty sure that the GT120 was faulty. At least now I know it's not a hardware issue.

Someone mentioned that it only seemed to happened if they were using or had FireFox running. In my case, I know I did have FireFox running the majority if not every time I got the crash. Has anyone seen this Log Out Crash when NOT running FireFox. I'm just trying to see if there is a pattern here?

That was me, but I had the same problem viewing my YouTube vidéos with Chrome instead of FireFox.

So if there is a pattern, it should be the fact to play somes vidéos and let the browser opened, in my case.

Without runing FireFox or Chrome, and without viewing YouTube videos on it, I don't observe any "back to login screen".

(3 GT120 - 6 screens)

I've had it happen with nothing but mail or photoshop open. It seems to happen without a doubt if I click on a tool in photoshop and the tool window opens on a different screen

Yes, that's the same symptoms as I usually get, clicking on something in one Window which opens another Window on a Monitor on a different Graphics card.

Hey guys!

Got the same problem since my (clean) install of 10.11. I already submitted a bug-report, please also do this. Append your system-configuration to help Apple to solve this asap. Also append your WindowServer-Crashreports.

My config:

MacPro 4,1; 2 Quad-Cores; 20GB RAM; GT120 (one monitor); HD7870 (non-flashed) with two monitors

I use the GT120 just to get a boot-screen (otherwise you can't login with Filevault…). I just ordered new cables to pull the GT120 out, because this log-out bug is preventing me from work. In fact, the WindowServer is crashing, that's why we get logged out.

I can not really reproduce this, but I can confirm it happens most often by interaction between the monitors that are not connected to the same graphics card. I use spaces and MissionControl a lot.

Apple, you really need to fix this. This is a serious issue.

it definitely seems like a problem with communication between 2 displays in a single program. If I open a few tabs on chrome, then try and drag one of those tabs onto another display it instantly crashes and logs out.once it is there after logging back in it is ok

Not to me. If I login, I can just sit there for a few seconds and it'll crash. If I log in again, it'll crash. I need not do anything once logged in, other than wait. It takes less than 30 seconds every time for me. I don't need to click on things, open windows, etc, it just happens -- fast.

Question for byte.it -- I've thought about replacing my nvidia cards with one or two radeon cards to stay closer to what the current Mac Pro is using, thinking it might be good for stability or performance. The reason I upgraded to 10.11 so quick was that recently my 10.10 system would slow to such a crawl each day that it was unusable. Like, five seconds to switch windows slow. A reboot makes it fairly quick again for a few hours, but inevitably I was toast by the end of the day. I don't need 3D performance, I just want snappy desktop behavior for the thousand office-y programs I run each day. Any opinion on whether moving to radeons might yield better-maintained apple support?

Same issue I have done all the suggestions from this thread. Hoping a lasting solution is presented soon. This one monitor thing really not working well for my production time.

What cards are you using?

What model MP?

If NVidia card(s) ae you using the NVidia drivers released yesterday?

In Mission control is Monitors use separate spaces checked?

I have 2009 MP wiht the original GT 120 and and a PC 5770 card.

I installed the Nvidia drivers released yesterday and no problem with one monitor on each card if User Seperate Spaaces not checked.

If I check that box I still get the log-outs.

NVIDIA GT 120 and ATI Radeon HD4870 on MP2009, Separate spaces unchecked and new NVIDIA drivers (6 October) installed and in use. Issue is still there.

THe two cases I remember best were:

- Dragging the mail view  from one display to the other

- Worked for a while on right display only, then simply clicked on the desktop on the left display, bingo ...