Yosemite + external display won't work?

Discussion in 'Mac Accessories' started by Thares, Jul 25, 2014.

  1. Thares macrumors 6502


    Feb 25, 2011
    Dresden, Germany
    Hey guys,

    I have a 2012 rMBP with the Yosemite beta installed. When I hooked it up to my Dell U2414H, my macbook just won't recognize it any longer. I checked every port (DP, DP, mini DP, HDMI, HDMI) and tried different cables. Does anybody have similar problems?

    It worked with Mavericks and Windows before. I can't test it with Windows because I deleted that partition.

    Thank you. Google was of no help for me.
  2. MCAsan macrumors 601


    Jul 9, 2012
  3. Thares thread starter macrumors 6502


    Feb 25, 2011
    Dresden, Germany
    Thank you. It's kinda odd because it worked before. And I switched between cables and ports. I thought about taking it to the local Apple Store and hook it up to a ATD to see if it works.

    Thanks again!
  4. silvetti macrumors 6502a


    Nov 24, 2011
    I can also say it works for me on PB1 with Mini DisplayPort to VGA adapter connecting to some LG monitor.
  5. thinkyhead macrumors newbie

    Dec 4, 2011
    MDP with HDMI Broken in OS X 10.10 Yosemite

    I am also having this issue on my MacBook Pro (15-inch, mid-2010). Since I installed Yosemite I can no longer use my ViewSonic HDMI monitor connected to the Mini Display Port. When I connect the plug to the laptop there is a screen flash, but it doesn't go to the next step and bring up the second monitor. It gives the impression that something might be crashing or failing.

    I have a second partition with Mavericks on the same laptop, and the HDMI monitor works fine with that system. So it's not the SMC or the PRAM, but something about OS X Yosemite that is preventing the monitor from working. I have reset both the SMC and the PRAM to make sure.

    As I look around my Console log, I see some references to com.apple.AmbientDisplayAgent ("AMBD Agent: xpc connection became invalid during event handler.") and there are some posts on MacRumors that seem to implicate this same Apple service.

    It's possible on my system that some display-related add-ons are incompatible with Yosemite. I have the apps "Stay" and "SizeUp" and I may try disabling them next. But I don't believe I have any display-related kernel extensions or anything like that. I have some extra drives, so I might try a completely fresh install of Yosemite also...
  6. arbrx macrumors newbie

    Mar 19, 2014
    I had the same issues once I upgraded - My 2013 Macbook Pro didn't recognize my LG monitor. I tried about everything I could to no avail, considered going back to Mavericks. While I would believe Apple will fix the issue (seems others are having same issue with no solution); here are some forum/blogs discussing external monitor issues and possible fixes (worked for me thus far):

    34" LG External Monitor Blog:

    Large External Monitor Discussion:
  7. arbrx macrumors newbie

    Mar 19, 2014
    Update to last post - My external monitor failed to work again from my previous post direction links. Once I de-selected "Auto graphics switching" under Energy Settings on my 2012 Macbook Pro, it worked again. Not sure if this may help others, wanted to post an update just in case it may help.
  8. philipkiva macrumors newbie

    Oct 25, 2014
    I'm having a similar problem. 2013 MBA, 13" display. Upgraded to Yosemite a couple days ago, haven't been able to get the external monitor to work since. I've reset the PRAM and the SMC. The external display is a Samsung LN46A650A1F. I'm connecting via Thunderbolt->HDMI. The adapter is manufactured by Monoprice.

    I appreciate any help. Thanks,

  9. KeanoL macrumors newbie

    Oct 30, 2014
    HDMI problem resolved for me...

    I upgraded to Yosemite yesterday - having had the word from Apple about how great it was - and apart from the awful "toy computer" look and feel the main issue is that it would no longer drive my Panasonic HD plasma tv, which means ITV player can't be streamed (BBS iPlayer is straight through the telly).

    Eventually I went to System Preferences / Mission Control and deselected "Displays have separate Spaces", then tried again - no luck.

    However, with this still deselected, the cable connected, and the HDMI input selected on the TV, System Preferences / Displays showed the correct TV. So, I took a punt that there might be a default settings issue, and switched from the default "1080p" to "1080i" and it is now working just fine.

    I don't have the technical knowledge to know what the real difference between the two setting is, but the screen image and sound all seem perfectly acceptable.
  10. Carlosgomes macrumors member

    Jul 3, 2013
    We have the same laptop and a similar problem.
    The only way I manage to connect my laptop to an external display is:

    1) Connect your laptop to the external display
    2) Turn off your MacBook
    3) Do a PRAM reset while booting
    4) Done

    This works for me, but for some reason, if I remove the charger or the HDMI cable and then insert it again, it won't work.

    Yosemite has been a disappointment so far, due to all these bugs.
  11. heehee macrumors 68020


    Jul 31, 2006
    Same country as Santa Claus
    I was connected a 2011 MBP to a Sony TV via HDMI to mini display port adaptor. I thought it was the adaptor not working, apparently it's Yosemite. I'll try resetting PRAM.
  12. CultHero macrumors 6502

    Mar 20, 2007
    Glad to see I am not the only one having this issue. My LG34UM95 stopped being visible to my rMBP today. I have been running the Yosemite Beta for a while and just today I had the issue.

    I know it is a graphics thing as my two drives that are connected to the display are still accessible to the laptop.

    This sucks.
  13. macgineer macrumors newbie

    Jan 12, 2015
    Same issue here.

    MacBook Air (11-inch, Mid 2013)
    Yosemite 10.10.1 (14B25)
    Dell 2210 External monitor

    I had to restart my laptop when it went to sleep, because than the external display stopped working. Then I have searched in many forums, did the SMC PRAM reset 3 times and since than my external monitor doesn't work at all.

    I have also repaired disk permissions, because it wrote. It helped nothing.
    Group differs on “private/var/db/displaypolicyd”; should be 0; group is 244.

    The console said: "AMBD Agent: xpc connection became invalid during event handler"


    So now I have no external monitor at all...
  14. 9to5Slavery macrumors newbie

    Nov 23, 2014
    I have the same issue too. Connecting to a projector with a display port(thunderbolt) (to HDMI) connecting to VGA HDMI adapter. Screen flickering on macbook and it detects on projector and then it doesn't.

    WindowServer: CGXSetDisplayColorProfileAndTransfer: Display 0x042737c0: Unit 0; ColorProfile {562068053 }; TransferTable (256:12)

    WindowServer: CGXSetDisplayAgent : AMBD Agent : xpc connection became invalid during event handler

    DMProxy: AMBD Services: connection interrupted: com.apple.AmbientDisplayAgent (Connection interrupted)

    com.apple.AmbientDisplayAgent : AMBD Agent: xpc connection became invalid during event handler

    kernel: EDID CEA Extensions not valid for audio [Revision Number]: 2 (minimum required value: 3)
  15. zionsvilletech macrumors newbie

    Jan 28, 2015
    Dual Display not working with LG 27" on Yosemite

    Same Issue. I was using 10.6.8 using the resolution of 2560x1440 with an LG 27" (27ea83-d model) Monitor using an adapter DisplayPort to MiniDisplayPort on a late 2009 core 2 duo imac.

    I have a similar one in year and size and it works on the other one. The main difference I have found is that the graphic card is different.

    The one that doesn't work is an ATI Radeon HD 4670 256
    The one that works is a NVidia GeForce 9400 256

    Both have the latest osx and 2009 iMacs.

    I have tried changing to vga, hdmi, different brands of adapters with no success. I have tried the normal fixes, resetting/fixing permissiongs... The monitor isn't equipped with thunderbolt or minidisplay port.

    I think I ran across tha NVidia has a separate driver download on their website but that is the one that works so no point for me trying that.

    I hooked up a smaller screen, I believe around 19"-23" and that works fine.
    It seems to be a issue with the LG 27" combined with Yosemite and the ATI Radeon HD 4670.

    It shows up in the preferences screen mode as detected as well.

    I have tried to delete various plist files associated with the graphics that were recommended on other sites to no success.

    I have tried additional resolutions with no success.

    If someone has a solution and if this helps anyone save some troubleshooting time please post a workaround or fix. I have found no additional downloads from ATI.

    We really do not need any expensive paperweights.

    I have not tried any buffer kext editing or doing a clean install.

    Hope someone finds a solution soon :)
  16. xaosnox macrumors newbie

    Sep 21, 2018
    I have the same problem with Yosemite 10.10.5 and a Sceptre monitor. I tried mini display/thunderbolt 2 to VGA and DVI adapters with no love. I bought a total of three different adapters, none of which work. I don't even have a "Detect Monitors" option in my Displays Preference Pane. When I plug in any of them, the Mac says there is nothing connected to the Thunderbolt buss, and the monitor says there is no input. I had someone haul the monitor and my MacBook Air to the Apple Store and they checked it with one of their adapters, and it worked. So, the moral of the story is, Apple found a way to make sure that they get the $30 bucks for the adapter that should have been included free with every Mac that doesn't have a display output. The only third party vendor that I would trust is OWC (macsales.com). They usually have something that is about half the price of the Apple product and is at least as good if not better than the Apple products. They've been the most reliable vendor for anything Mac related for at least 15 years that I've been shopping with them. And, no, I don't work for them.

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