3 Replies Latest reply: Jul 17, 2013 3:24 AM by AdriHD
AdriHD Level 1 Level 1 (10 points)



I've got a MacBook Pro 2011 with OSX ML (All up to date). SInce I've had it and used it via the TB -> HDMI (used several cables which are Apple originals) THe HDMI flicks out and back in again as if I've opeed the lid.


The main reason why I say this is because the Apple on the laptop in ClamShell mode flickers (as it does when also wake the notebook in clamshell with the HDMI connected).


I've got a Samsung television about 5 years old, which works fantastically with the myriad of other HDMI devices I have connected to it. The only issue seems to be the MacBook.

Here are my Settings & Preferences:




Resolution: Best for Display (I've also tried the Scaled too)

Rotation: Standard

Refresh Rate: 60 Hertz NTSC

Underscan: Off


THis has happened on OSX 1.06, .7 and now ML. On other televisions I don't notice this issue at all, itonly appears to be with this one in particular.


I've had a look at Console and trauled through the logs when it happens, and all I can see is that the display, momentarily can't be found.


I can confirm this doesn't happen in BootCamp Windows 7 Pro x64, so I'm at a loss as to what to do.


The sound works perfectly, though once in a bluemoon I get a weird 'stutter effect' where the stutter gets slower, and slower until the sound vanishes. THe only way to restore the sound is to flip input to another or turn the TV off and back on again.


Is anyone else experiencing these issues?


The ONLY thing I can think of which differs on this TV from my others, and those at friends houses is that being Samsung it has something called Anynet+, which is like Toshiba's Regza and Sony's Bravia. Which works find with my sound systems, IPTV box and the other devices.





MacBook Pro, OS X Mountain Lion
  • 1.
    brenden dv Community Specialists Community Specialists (3,015 points)

    Hi AdriHD,


    It sounds like you've been on the right track in troubleshooting this issue. You may want to double-check the troubleshooting steps in the following article to see if it helps isolate the issue:


    Apple computers: Troubleshooting issues with video on internal or external displays




    - Brenden

  • 2. Re: 2011 MacBook Pro - HDMI Flickers Every Hour or Two
    AdriHD Level 1 Level 1 (10 points)

    Thanks for that, but I noticed something else recently since I set the energy saving to high.


    When it wakes from sleep, it only does that. I literally have to turn the TV off and back on again to rectify it permanently :-/


    This doesn't happen with any of my other HDMI gadgets... Seems to be MBP specific. Not sure if it happens on the Mac Mini too...


    The hunt begins


    I've even updated the TV firmware and that didn't make a difference. The odd thing is that the flashing off and on i.e. losing signal is very intermittent. Another odd thing is that sometimes it just presents itself as a quick flash of snow (i.e. like the old CRT televisions that weren't tunes in), or it completely loses the signal for a few seconds and comes back on, repeats this randomly 2 or 3 times and then stays on for between 5 - 10 minutes before it happens again.


    I've actually sat patiently and timed it and the results varied alot. Still, there's nothing in console logs to indicate that it's anything that OS X is doing wrong (or not something it knows it's doing wrong).


    As explained it's weird that this doesn't happen in Bootcamp. But I think you'll be glad to know I've finally deleted the Bootcamp partition and got rid of that parasite that plagued me for years!


    Do you have a writeup or an  article I can look at about putting the graphic drivers into debug/verbose mode so i can see what's happening? THe only way I know is getting the IOKit extensions and Debug Kernel etc... from the developer site. But I'd rather not do that to a production Mac! I was hoping of something easier i.e. boot time flags etc...


    Cheers and thanks for your time so far!





  • 3. Re: 2011 MacBook Pro - HDMI Flickers Every Hour or Two
    AdriHD Level 1 Level 1 (10 points)

    could you possibly give any feedback based on my findings? I'm concerned this could be a general issue as I'm debating about one of the new Mac Pro's (or AshTray Pro as my non-apple buddies call them) lol