• MacPro late 2009 with 3 monitors. OSX 10.11.1
  • Will run great on 1 monitor without screen/system freeze or logouts. At times it is an instant logout, other times, the primary monitor freezes, or is filled with weird graphics. NVIDIA GeForce GT 120 512 MB
  • Began with 12 G Ram and upgraded to 24 after having problems with El Capitan. Suspected OS memory leak.
  • Then did full erase and OS install, but before restoring my data, created new user and used Safari to test. On each monitor, a Safari tab streaming news videos. Ran for hours, but when I started using the system, it had video problems and locked up or logged out. Don't remember which.
  • Then restored all my backup data and settings.
  • Activity Monitor shows full 24 G installed, but the Memory Used and Cached Files never go above 12 G
  • TechTools 8, all test pass. Memory, video, temperature, fans etc.
  • Apple Care 2nd level tried to no avail.
  • System performed flawlessly until El Capitan install
  • System now is totally unreliable. I installed 10.11.2 yesterday and am hopeful that fixed it for me as it has many others. I'll update.
  • It appears that 10.11.2 has fixed it. This was the first time I had an update go bad, thankfully. Communication would go a long way, but results are always appreciated. I still feel they (Apple) are the best horse in the race. BTW here is the Apple Support thread on this; https://discussions.apple.com/thread/7252069?start=0&tstart=0
  • Everything you say would make me suspect overheat or underpower [GPU or PSU fail, especially pushing 3 screens from a GT120] except for the term 'logout'. Do you literally mean it logs you out & presents you with the user login screen again, or do you actually mean it crashes/reboots? If it's a true logout, then I'd try setting up a new admin user & test it under that.
    – Tetsujin
    Commented Dec 10, 2015 at 13:02
  • 1
    Yes, I'm presented with the Login screen. I forgot to mention that Apple support had me add another user. The new user also gets logged out. Also when I had reloaded and before any of my data was reloaded, I exercised the system. I opened Safari, (normally I use Chrome) by opening a tab on each monitor and playing a news video. It eventually logged out.
    – stevejohn
    Commented Dec 10, 2015 at 13:25

1 Answer 1


From https://support.apple.com/kb/PH21782:

OS X El Capitan: Set your Mac to log out when not in use

You can set your Mac to automatically log out the current user after a set period of inactivity. This helps ensure that your information is secure when your Mac is unattended.

  • Choose Apple menu > System Preferences, click Security & Privacy, then click General.

  • Click the lock icon to unlock it, then enter an administrator name and password.

  • Click Advanced.

  • Select “Log out after... minutes of inactivity.”

  • Set the amount of time before the user is automatically logged out.

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