MacOS – External monitor stopped working after 10.9.2 update

displaydisplayportmacbook promacos

I've been using a Dell U2713H display for about a year with a mini-display port to display port cable.

However, after installing the 10.9.2 update, the monitor is going into sleep mode when connected to the MacBook Pro (as it doesn't think it's getting a signal), even though the laptop thinks it's correctly connected. (If I turn the monitor off, the menu bar, etc. revert to the MBP screen.)

About the only related Mavericks default I've changed is to disable the "Displays have seperate Spaces" option within Mission Control, although I've tried re-enabling this and logging off/on again to no avail.

I've also tried:

  • Forcing the system to use the dedicated GPU rather than the on-board chipset.
  • Resetting the NVRAM and the SMC, neither of which appear to have made any difference.
  • Re-installing the 10.9.2 update
  • Creating a new user account to see if there was a user specific problem
  • Booting in safe mode to ensure no 3rd party apps were affecting things
  • Forcing a re-detect
  • Deleting the /Library/Preferences/ file (getting desperate here)
  • Clamshell mode
  • Using the EDID override approach (As per:

After looking into this more deeply, System Information states that the monitor is a TV and I wonder if that could be related to the problem.

screen grab from System Information app

My Mac is a 15" MacBook Pro Mid 2010 model.

Best Answer

  • I've just managed to workaround the problem by disabling DisplayPort 1.2 within the Dell OSD.

    To do this, you might need to use a bit of a workaround, which is to get the monitor to bring up the input select and then hold down the green tick for ~8 seconds when the (mini-)DisplayPort option is selected. This will bring up a new menu that enables you to enable/disable DisplayPort 1.2 mode. (Green tick to enable/red to disable, etc.)

    Whilst I suspect this is just a temporary fix, it at least means that I can use the monitor until Apple fix their seemingly problematic 10.9.2 release.


    As an minor update, my bug report has been closed as a duplicate and due to the nature of Apple's "closed" bug tracking system I've no means of viewing the other ticket. However, at least this is a known issue that will presumably be addressed in a successive release.