Apple iMac Users Experience More Graphic Anomalies



There have been a some reports that followed the release of Mac OS X Lion from iMac users complaining about graphic or video problems.

One user reports that he’s been experiencing video artifacts on his 2011 27-inch iMac configured with a 3.4GHz quad-core Intel Core i7 and AMD Radeon HD 6970M graphics processor with 1GB of GDDR5 memory. It’s been fairly intermittent and it always disappears for a while after a restart.

Today the problem was so different and a lot worse than usual that they finally decided to call AppleCare.

Here are the graphic anomalies that he saw on his iMac.

The task switcher is involved and so is the menu bar. The menu bar exhibited the same graphic anomalies where ever there was text displayed.

Relaunching Finder did not resolve either issue and a hardware test didn’t turn up any hardware errors. A call to AppleCare and speaking with a Senior Advisor hadn’t turned up a solution at press time.

I’ve seen some similar graphics anomalies on my 27-inch 2011 iMac and they usually vanish for a while after restarting. However, I also see mine appear on the lock screen when it prompts me for my password to unlock my iMac.

Are you still experiencing graphic anomalies on your iMac or other Mac after upgrading to Mac OS X Lion and installing all the latest updates?

  • DysonApps

    This happens to me when I’m using remote desktop. Annoying.

  • mine doesnt to that but just every now and then got back and my second monitor says no signal?

  • Michael Rials

    I’ve seen similar things when logging in as flashes in sections where the login icons were but they disappear immediately and a couple times when using a graphically intensive app when I close it there will be similar appearing anomalies but they’re flashes

  • SteveK

    I’ve noticed it on my 3.4Ghz 2011 as well. I see it occur when viewing a youtube clip and then get very blocky artefacts in a finder window as well. I can’t tell if it’s a Lion issue or not as the machine was born with Lion installed.

    I’ve noticed similar issues with my 2011 mac mini as well. Definitely Lion related and most likely graphics drivers.

  • joshuah82

    I have a 2011 27″ i7 3.4GHz with the 2GB 6970M. I get this graphical issue quite often. It seems to appear randomly while playing Flash videos and can only be resolved by a restart. This is my first new Mac after being a long time PC builder/user and it’s not the experience I expected from Apple.

  • Ernesto

    Only problem I see on my 27″ iMac is when going full screen watching a movie clip the monitor turns white.
    Haven’t heard of a fix yet.

  • Smartartiist

    This and more has been happening to me, I’ve been meaning to cal Apple care. I first saw it when I used quick look on a pic from an external hard rive. The issue has lessened lately though

  • Greg

    This is my 8th mac, and my 3rd imac…no issues like this whatsoever.  I work from home and use my mac 8-16 hours/day.  The only issue is theres not an all in one bigger than 27 inches.

  • A Name

    27″ mid 2011 iMac. I have the same problems, occurs after resume from sleep, clears up after reboot.

  • scottdot

    No problems here with a 27″ (2011) Core i5 2.7 GHz with the RadeonHD 6770M 512MB. Hope they can fix it with a firmware update and not a recall. How annoying…

  • ?psq@

    same problem but i like glitch art so i dont mind

  • kalevi

    Yep, the same has happened for me too. It usually appears after watching 720p YouTube clip or just playing .avi files on QuickTime. It’s annoying like damn, but gladly, restart fixes the problem.

  • Sbmorar

    Same here, i had it appear on the lock screen, disppeared straight away but have a 3.4GHZ i5 2011 iMac model 

  • Jeff

    Just bought my new iMac two weeks ago.  “27, came with Lion.  Playing movies purchased on iTunes, before and after the migration from the old iMac, is stuttery and choppy, but not the sound.  I finally called AppleCare.

  • Debster

    I’ve been getting strange artifacts similar to that on my 5-yr-old iMac running Snow Leopard. Increasing the fan speed helps somewhat, but it’s certainly an annoying problem.

  • Josh S

    Yes, it seems almost every 2011 27″ iMac with the 1gb or 2gb graphics card running Lion has the issue, including mine. I started a discussion on the apple support forums and I currently have 114 replies all with the same issues, theres multiple other threads about the issue too, heres the link to mine:

  • Caki4703

    There are also other graphic issues on my mid 2011 27″ iMac with Radeon 6970 with 2G. Like scrambled Finder lists and scrambled graphics in Omnigraffle:

  • ViteriF

    Wait, so did the users that are experiencing these problems upgrade their OS to Lion or did they buy an iMac with Lion already installed? I’m in the process of getting an iMac within the next couple of days and hearing about this problem is a little disheartening… 

  • Bdevaux

    I’m getting screen going black with my mini with nvidia 330m

  • jjwalker

    i am having scrambled finder lists as well, especially when looking at an external hard drive in finder.  I also have issues of “the matrix green screen” like video playback on itunes, youtube, etc.

  • Alessandro

    please apple fix it….from july i have this issue

  • skilby73

    I have had this issue on one occasion, not as severe as in the article. I have the same 3.4ghz iMac. I asked around on twitter at the time and no one else had seen it. Seem to be isolated to the 2011 iMac. I hope they fix this soon!!!

  • strpyw

    I have similar scrambled finder lists on my imac similar config as  yours

  • gnomehole

    I’m seeing them… I simply reboot.   I think it usually happens if I fire up Parallels and Windows 7 but haven’t isolated it.   

    Still rebooting way less than I ever did in Windows but wouldn’t mind Apple fixing this.

  • intrepidsilence

    I am seeing this exact same issue.  Same here – reboot fixes for unknown time period.  Have rebooted with a test account in safe mode and it still happens so it does not appear to be anything that is installed on the system.  I have also noticed that when I open the Console and scroll up and down, eventually it corrupts into “blocks” of gibberish.  This is easily repeatable and happens anytime I use Console, even in safe mode.  I have the 27″ iMac 3.4Ghz i7 with 6970 2G VRAM.

  • michaelismichael

    I also have a 2011 27″ iMac with the 3.4GHz Sandybridge and the 2GB 6970M GPU and an SSD. This has happened to me, as well as scrambled text in the Dictionary app after scrolling down. I’ve also had purple and green vertical streaks in the screen after the display turns itself off.

    All goes away after a restart (the streaks go away after a minute or two) but I plan to bring it in soon. I’m not happy, especially after reading that I supposedly bought the best Mac they have ever made.

  • Visimex

    I’ve got my new Imac 27″ 3,4 GHz with AMD Radeon HD 6970M 1GB (came with Lion installed) for just 1 week and have the similar problem in Finder and Console. 

  • Bob Forsberg

    Reading the comments, the problem seems isolated to the 3.4Ghz processor.

  • Scada

    Same issue here. Seems to have something to do with video in safari and click to flash H.264 video.

  • Jeff

    Same issue.

    iMac 3.4GHx Core i7
    AMD Radeon HD 6970M

  • Shirley Lacroix

    Same here with 2011 27″ that shipped with SL and now has Lion. Apple Care captured info from my system yesterday. Lots of scrambled screen in Finder especially if folder has lots of files and folders to scroll through. I work 8-10 hrs per day on this system and it seems to happen more late in the day. No Parallels on this computer. Yesterday, while trying to play QT movie it scrambled the gray in the finder windows. I have pictures but am hoping an updated Lion will give us a fix!

  • boxcarmib

    Not so. I have the 3.1 Ghz processor and experience the same issues mentioned here.

  • boxcarmib

    “still rebooting way less….” — Spoken like a true Windows user. As an ex-windows user you may believe it or not, but rebooting has never been considered an acceptable “workaround” for Mac issues. in the twenty odd years I’ve owned macs (and pc machines as well)…. I cannot recall having to resort to rebooting a mac to address a problem except in very rare and unusual circumstances. That’s just one of the things that makes this issue so annoying. I rarely turn off my machine, and only reboot when a system upgrade requires it, but since installing Lion I’m having to reboot two or three times a day to clear up these screen issues. What angers me most of all however, is Apple’s willingness to MAKE me into a windows-like reboot slap happy user.

  • SteveK

    Yup, I’m seeing that too. Glad someone was able to capture it because when I went looking for the issue it just didn’t want to appear.

  • Caki4703

    The issue does not occur when booting into safe mode.

  • intrepidsilence

    Incorrect.  I specifically tested in safe mode and the problem was still very easy to reproduce.

  • Jerrygoshen

    I’ve been having graphics issues since installing Lion on my 27″ 2011 iMac.  Apple doesn’t seem to care to fix the issue.

  • Rick

    What are your machine’s specs?

  • Battledancer

    bought with OSX lion installed.  Have heard the issue from other users who upgraded, causing them to eventually go back to snow leopard.

  • SBacklin

    I believe I experienced this issue for the first time not that long ago.  I was trying to watch a video on youtube and it wasn’t loading very fast and so I was trying to go back and forth, trying to find another source of that video.  Then I noticed graphics glitches within the video itself.  The menu bar text was all greyed out.  When highlighted the text became a single block of darker grey.  The  widgets/gadgets on dashboard looked like the items in the picture in this article.  After a restart, everything was back to normal.  I hope that this is something that can be fixed with a s/w update.  My specs are:  Mid-2011 iMac, 27in, 3.4 Core i7, 2GB of video RAM, everything else is stock.

  • Jeff

    Same issue on my 3 week old 27″ iMac. I had been noticing oddness when scrolling in Finder also some odd flickering that seems to be isolated to the upper left hand corner, now tonight I was playing a 1080 HD YouTube video and it started flickering Pink like mad, switched to 720 and it went away. Then when I exited full screen mode, craziness was rampant. Application switcher looks just like the screenshots in the article, menus are all messed up. Reading through the threads on the Apple forums is disheartening as apple has not done anything to address this issue. It really seems to be a heat issue, though based on the fact that folks did not have this issue prior to Lion it would seem to be a fan control/temp sensor problem with Lion. Guess I have to call Apple and hope that they have a clue about this (doubtful) and that they do not seriously expect me to drag a 27″ iMac into the local mall.

  • Technoguy3

    I have had this exact same issue ever since upgrading to Lion! It’s driving me nuts!

  • Technoguy3

    It seems limited to 3.4Ghz Intel i7 users.

  • intrepidsilence

    New info for anyone watching this thread…

    I uninstalled Perian about 2 weeks ago and have yet to see this kind of artifacting since.  Can someone else do this and confirm?

  • sgenzel

    Same graphics issues on iMac 27 3.4ghz 2gb Grapics card bought July 2011

  • Moctavian

    In my case, the artifacts are tied to watching flash/html5 video on/off youtube in fullscreen (that includes Plex and other apps that have some sort of youtube/flash plugins). Logging out of the OS gets rid of the artifacts until I watch some more youtube videos.

  • Palm

    Artifacts in Finder

    iMac 3.4GHx Core i7
    AMD Radeon HD 6970M

  • Redirocks

    same exact problem here!
    3.4 ghz quad i7 27 inch 16 gigs of ram,2 gig amd 6970m

  • Rwill51

    Similar problem here with
    2011 27″ 3.1 GHz and AMD Radeon HD 6970M 1024 MB graphics that shipped
    with SL and I updated to Lion. Bought it new two weeks ago. Parts of screen
    scrambled in Finder especially in folders with many files/folders to scroll
    through. If I scroll so problem is off screen and back it will usually correct
    itself. I have not been doing any demanding graphics so can’t see it as a
    heating problem. I just reproduced
    problem and back of iMac is just warm to touch at top back. One other issue but still related to graphics. When
    the iMac is left and it goes into sleep mode if I attempt to wake it the screen
    opens completely gray. If I move the
    mouse (no cursor visible) small boxes of the logon screen will start to appear
    in its wake but after moving around a little the full logon screen
    appears.  Bazaar!

    I’m hoping an update to
    Lion will fix but mine is completely updated and still problem persist! Anyone
    heard any encouraging news?

  • Masterspook

    Photoshop CS5 exhibits bizarre glitches: random resampling of image resolution after cropping; random inversion patterns in multiple layer files.  A nightmare!  The finder does not even perform simple functions such as remembering window view settings or item numbers of folder contents. Noticeably slower performance in general.  This is mac, right?  I mean, Lion isn’t some pernicious windows virus is it?  Feels like it.

  • Bryce Kim

    Anybody had this problem since 10.7.2?

  • strpyw

    happy to report problem solved with new software update

  • Robert Klostermann

    I have the problem on my Macbook Pro5,5 13″ (Mid 2009) and the latest Lion (10.7.2). See… and

  • Robert Klostermann

    I have the problem on my Macbook Pro5,5 13″ (Mid 2009) and the latest Lion (10.7.2). See… and