Help with a older mac with purple vertical bars on screen, possibly getting rid of it?

So, I have a 2011 imac that just started acting up. The computer would lock up and sometimes when we reboot, there are purple vertical bars on the bootup screen (the one with the apple logo). I normally let it sit but it just gets to a white screen of death.

I reformatted the hard drive and installed 10.13 on it, and everything seemed to be fine until this morning when it acted up again.

SO… I have two qutestions:

  1. Has anyone seen this issue before? What can we do about it?

  2. If this does have some sort of hardware issue, what is the best way to dispose of the mac.

Thanks in advance!


Can’t help with your hardware issue, but if you decide to dispose of your iMac, there might be a local charity that refurbishes computers as a part of job skills training, etc.

Apple will recycle your Mac for free if it has no trade in value.

I had this on am old machine and was a known issue with the graphics card. I think from memory it was Nvidia. At the time Apple replaced the chip (I think) even though it was out of warranty.

If you do a search online for it you will find it quickly, unsure if they are still running the repair option though.

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Yes… you probably have an issue with the graphics card on your iMac.

Yes… a 2011 iMac is an old computer and may be considered Vintage in Apple’s eyes. That means parts may not be available for a repair or cost prohibitive.

No… your iMac does NOT suffer from the Nvidia issue that was common on 2010-11 MacBook Pro models. Apple’s Quality Program for those models expired years ago.

8 years is a great run for any computer… but it is time for something newer. I think you would be wasting your money trying to keep this one running.

That is a problem with the graphics card. These cards have fairly poorly manufactured heat management; instead of thermal paste to heat-couple the GPU to heat sink, they use a padding material. The pads are much easier in a scaled production environment but they dry out over time causing your GPU to over heat. An addition problem you may have with this card is that some solder contacts are eroding, causing the GPU to fail.

Apple replaced these cards for free for quite a while after the warrantee. They replace them now for about 450 (us dollar). First time it happened to my 2011 imac was 3 years ago and they replaced for free, had the unit back in 3 days. Very nice. But since then it failed again and so did my wife’s and son’s (all same machines).

The good news is you can restore these cards to work normally again. The bad news; it is a bit of work. I have restored all our Macs and a few in our neighborhood (word got out)

You need to remove the card, and remove all padding. The card needs to be baked at 200 deg C for 8 minutes. Use thermal paste (messy stuff) to form contact with heatsink. When you do this, be sure to clean the GPU really well, it has a high polish finish (black) you need to see before putting on new thermal paste.

First time it took me over a morning to fix the card, now it is about 1.5 hours. It is perhaps a bit scary at first but entirely doable.