Occasionally my macbook pro (15-inch, Early 2011 with mountain lion 10.8.2) displays random garbled blocks. This happens on external Apple displays and the laptop display. See photo.

enter image description here

  • Are you using gfxCardStatus by Cody Krieger? (If yes, update to the latest version.)
    – MacLemon
    Sep 29, 2012 at 19:12
  • This problem continued to persist. I had to get the logic board replaced to fix this issue Jan 23, 2014 at 20:36

1 Answer 1


We had a lot of these problems in our store and in the most cases the graphic card was broken. You should run the Apple Hardware Test / Apple Diagnostics and look at the results.

  • I've had the same thing on two machines. The graphics card was bad and Apple replaced it under warranty. In one case, twice in about 5 weeks.
    – Ɱark Ƭ
    Jan 21, 2014 at 17:13

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