Skip navigation

2011 iMac flickering when switching between desktops...

281 Views 4 Replies Latest reply: Nov 19, 2012 4:05 AM by chadstyle RSS
chadstyle Calculating status...
Currently Being Moderated
Sep 3, 2012 1:48 PM

I'd like to start by saying that I generally am able to google any issues I am having and find a solution just by reading about others with the same problems.  Unfortunately this problem has been haunting me for a while now and I haven't found a solution... 


My 2011 21" 2.5 Ghz iMac with 16gb of RAM and 2tb HD running OS X Mountain Lion has been flickering when I scroll left or right between desktops.  Its a few horizontal lines that look jagged and the edges of any windows that are open distort for a brief second.  This happens all of the time.  Even with no apps running and the computer is nice and cool with no fans running it still does the same thing.  It first started a few months after purchasing the iMac while running Lion and I could restart the machine and it would stop glitching/flickering for a couple days and then it would return.  Now its there all the time and even though it doesn't seem to affect the performance of the machine I worry that it may be a sign of hardware failure to come and it just looks bad when it happens.  I have a Retina MacBook Pro, a 2010 27" iMac, a 2010 MacBook Pro 13", and a 2009 MacBook Pro and all are running Mountain Lion and none have this issue.  This computer is the one I do the majority of my work on so it's frustrating that I can't solve this problem.


Any help would be greatly appreciated!!  Thanks in advance for taking time to diagnose the issue...



iMac, Mac OS X (10.7)
  • jacfrombasel Calculating status...

    I had the same issue with few horizontal lines that look jagged and the edges of any windows that are open distort for a brief second.

    however i found today the solution. i may be luck but it worked for me. I opened my autocad version 2013 updated it and suddenly the horizontal lines by switching desktops dissapeared.

    So that make me think that it could be an program issue interfering with mountain lion.

    check all your programs you recently installed and update them.

  • TaDeX Level 1 Level 1 (0 points)

    I have the exact same issue, also with Autocad. I'm going crazy, because can't find any solution.

    In addition, I get the same glitch while playing a video on VLC.


    Anybody has found any hint to solve it?


    (Macbook pro 2011...)


More Like This

  • Retrieving data ...

Bookmarked By (0)


  • This solved my question - 10 points
  • This helped me - 5 points
This site contains user submitted content, comments and opinions and is for informational purposes only. Apple disclaims any and all liability for the acts, omissions and conduct of any third parties in connection with or related to your use of the site. All postings and use of the content on this site are subject to the Apple Support Communities Terms of Use.