Currently Being ModeratedNov 2, 2013 1:44 PM (in response to profputr)
It sounds like your monitor was workinf fine before you upgraded to OS X 10.9 but now is not recognized. I recommend the troubleshooting steps from this article named:
Apple computers: Troubleshooting issues with video on internal or external displays
No video or no signal, image distortion, "snow," or flickering
When using an external display be sure to check the following:
- If you're using an Apple notebook, confirm the AC power cable or adapter is securely connected to the computer and the cable providing power to the display is also secure. It is always good to have your notebook connected to AC power when an external display is in use.
- Confirm display adapters are fully seated in their respective connections and that they are supported models and for the computer and display. Refer to these articles to assist you with adapter compatibility and further configuration information:
- Remove all display cable extenders, KVM switches, or other like devices and retest to determine if the issue is resolved.
- Try unplugging the video adapter or cable and then plug it back in.
- If more than one video adapter is in use (or "daisy-chained"), troubleshoot by using only one adapter.
- Example: A mini DisplayPort to DVI adapter connected to a DVI to HDMI adapter is an unsupported configuration because there is a series of adapters in use.
- If available, try using a different display and or adapter (or use a different connector by using DVI instead of VGA, for instance).
Reset the system
You can reset the Mac's parameter RAM and SMC.Reset the resolutionStart by resetting the Mac's parameter RAM. If the display does not come up, was previously set to an unsupported resolution, and still results in no video:
- Start up in Safe Mode.
- From the Apple () menu, choose System Preferences.
- Choose Displays from the View menu to open the preferences pane.
- Select any resolution and refresh rate that your display supports.
- Restart your computer.
Thank you for using Apple Support Communities.
All the best,
Currently Being ModeratedNov 15, 2013 10:48 AM (in response to sterling r)
I have done all the above on my 2011 iMac with DVI ->Thunderbolt/mini adapter, but still have no picture - just the occasional flicker of a faint image. Also, unchecked "Dispalys have diferent Spaces" in Mission Control.
I really need that display for educational purposes...any other possible fixes?
Currently Being ModeratedNov 26, 2013 8:16 AM (in response to profputr)
Did you try "Detect Displays" (hidden in the Diplsay Preferecne Pane). System Preferences > Displays > then hold down the 'Option' button and note the 'Detect Displays' button that appears in the botton right. Click it. Might not work - but worht a try.
Currently Being ModeratedDec 12, 2013 12:02 PM (in response to profputr)
I'm having the same problems. This is really problematic for us, to the point where our CIO is considering throwing the Macs out for Linux. Frustrating.
Did anyone find a resolution to this problem? We're on a 27" Cinema with a Mac Mini Server.
Currently Being ModeratedDec 17, 2013 9:02 AM (in response to profputr)
I get this problem on my late 2009 macbook pro with an external dell monitor connected with a dvi adapter...
Sometimes to get it to work when it won't see the 2nd monitor,
- I unplug the DVI cable then shut down the laptop
- start it keeping the 2nd monitor unplugged,
- once I am logged in, I plug in the 2nd monitor DVI adaptor and usually after a few plug and unplug attempts; the second monitor usually gets recognized and starts working again
this supremely frustrating and time consuming work around has been the only way i have got my 2nd monitor to work since the latest mavericks update....
Currently Being ModeratedDec 23, 2013 7:56 AM (in response to BlackRockWeb)
quick ammendment, unplug the dvi cable and then unplug the monitor from the dvi cable... then shut it down...
once you are logged in and everything is loaded, then plug in the dvi cable, and then connect the monito cable to the dvi cable...
following this process is the only way i can get it to recognize my dvi cable.
display mirroring is still not showing up in my menu bar, but everything else is g2g at least...
Currently Being ModeratedDec 29, 2013 4:29 AM (in response to profputr)
I have the same problem as BlackRockWeb. The original OSX Lion that came with my Macbook Pro recognized my external monitor right away (AOC e2343Fk). This problem started after a software update that followed a year of no problems. I have no problems with my Windows laptop recognizing the monitor.
Currently Being ModeratedJan 18, 2014 7:26 AM (in response to sterling r)
Sterling, I have had this exact problem on several versions of OSX. It was always quite easy to fix by click the "Detect Displays" button in display preferences. However, this is gone in 10.9. Can I still run this command via terminal, do you know why it was removed or what it's equivalent is? It was such a simple fix, and I am frustrated to see it removed.
Currently Being ModeratedJan 18, 2014 7:31 AM (in response to scottcf4)
Actually I just found this article about the detect displays command. Works great and is very easy! I am using DVI to Thunderbolt also with an older Acer monitor.
Currently Being ModeratedFeb 21, 2014 2:05 PM (in response to KillDash9)
Thank you! I have no idea how you figured that out, but it worked!