I have iMac 2010 which is out of warranty. I recently came up to the computer and it was sleeping and was not waking up. I held the powered button for a while, so it turned off. Then I pressed it again. The iMac turned on, but I saw colored lines on the white background with apple logo and activity indicator spinning. It was spinning for a bit then the screen changed to checkered color lines and white background, and it froze that way. I turned on my TV that the iMac is connected to and all I see there is white screen. I tried cmd+Option+P+R and it did restart, but same thing happened. I also tried plugging out all the cables, including power. Waiting for few minutes and plugging them back in, but that didn't help. What else can i try? Do you think the monitor is dead or the video card? Hopefully not the hard drive. Here are the screen shots of what happens:

Loading Screen

Frozen Screen

I am trying to do as little as possible, not to loose the data. I don't have much backed up.

I found the diagnostic CD and was able to run it. I ran the quick test and it found no issues. Now I am running the extended test. Would the extended test detect bad video card? I tried to start the iMac in Safe Mode with the same result. What are my choices, if it is the video card? To change it I would probably have to replace the whole motherboard, and Apple will charge I am sure over $300 if not more. Is there a way to boot from a flash drive to let's say Ubuntu and access the hard drive?

Here is the screen shot from that Diagnostic screen:

Diagnostics Screen

  • 1
    The best way to narrow down the problem is to plug in external monitor to see what is the problem. And to start in SAFE mode to eliminate drivers conflict.
    – Ruskes
    Aug 12, 2013 at 7:46
  • 1
    I would suggest FireWire Target mode to save the data. In order to do that you'll need a another mac and a FireWire Cable. In FW target mode, your iMac will be seen as a FireWire Drive by the other Mac. Aug 12, 2013 at 12:48
  • Would that work even though i can't boot into the desktop. I only have the macbook pro that doesn't have firewire. Do i have any other options? Is there a way to turning off the iMac screen and use the tv as primary through the display port?
    – Yan
    Aug 12, 2013 at 12:50
  • Yes. You don't need to have an OS for that. Aug 12, 2013 at 20:20
  • Thanks for the help. I went to the apple store and they said it is the video card and $200 to fix it. I decided to let them fix it. Hopefully they will not touch the hard drive and i am not going to loose any data. I would think there is no reason for that.
    – Yan
    Aug 13, 2013 at 15:43

1 Answer 1


What you show us here are typical symptoms of a dead video card.

  • 4
    → Yan: stop experimenting with your iMac and cables, if you don't want to lose your data. Just run Apple Hardware Test: support.apple.com/kb/ht1509. If your video card is dead, this might be clearly visible from the start of the test, but you won't risk to damage anything else.
    – dan
    Aug 12, 2013 at 6:46
  • I posted an update to the question. How would i see if the video card is dead? Is it the lines or is it possibly the monitor is dying. My guess because i am not getting the desktop most likely is the video card. Thanks!
    – Yan
    Aug 12, 2013 at 12:30

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