Mid 2011 iMac Graphics Problems with Yosemite

I have same problems, GPU (AMD Radeon HD 6750M 512 MB) doesn't render as in Mavericks or OSX previous.

In addition the virtual machine on vmware and parallel are unusable [ Has anyone tried it? ]

PS: Thanks for trasparents tips 🙂

I forgot to mention that while Yosemite was slowly murdering my video card, although I could use Safe Boot and the Recovery Partition, I couldn't use OS X or Boot Camp.

If you're unsure what the cause of the problem is, try loading your Boot Camp partition. Straight after selecting it from the Boot Manager, my screen would go completely blank, and would stay that way indefinitely.

At the time, I was so focused on "fixing" OS X, I had completely ignored Boot Camp. Since I hadn't touched Boot Camp in weeks, I was surprised to learn that it had also mysteriously developed video problems, right from boot. Learning that earlier would have helped clarify whether the issues were software or hardware based, and saved a lot of time.

So, if you're also having video problems with your Boot Camp installation, you could be experiencing failing video hardware.

Smashmedia,

I do have the same iMac with AMD 6750 in stead of the 6770 everyone is having trouble with. I have no issue whatsoever, yet, but as a precaution deleted Flas player and turned transparency off. However, VMWare has been rendered unusable you have to upgrade (i.e. buy a new version). VMWare does this more often, so I deleted it and the virtual machines and am turning to boot camp.

So, let me throw a kink into this discussion. I own a 2012 (First Thin Model) 27" iMac with Nvidia 680MX video card with 2GB Ram. I am getting these same issues. After I upgraded to Yosemite, I first noticed little black squares where the rounded corners of windows would be. Then I noticed the whole windowing system being very slow. I could drag around windows by the title bar and see the whole rest of the window lag behind the movement.

Anyways, I did a little digging and found that Quartz Extreme was disabled. This is what was causing all my problems. Something is going on with the graphic card drivers/video drawing system that is causing Quartz Extreme to not be supported. I couldn't come up with a solution so I Time Machined back to Mavericks and haven't had a problem since.

Everyones fixes with Transparency and uninstalling Flash is working only because those features/programs use Quartz Extreme (QE). You just aren't seeing the problem anymore because you aren't using anything that is requiring QE.

I don't know the fix and I don't know why a specific subset of us are getting this bug, but Apple really needs to fix this.

Any of you having issues with the 6770 video card after upgrading to 10.10.1?

I have 2.7ghz 21.5 mid 2011 (manufactured Dec 2011) as well (mine shipped with Mac OS X.7 so never had snow leopard on it) currently running OS X.9.5 and have no issues with the card - i did not have issues with the card in the beta which is installed on a different partition. I was planning to update to 10.10.1 in the next few weeks but will not unless the graphics issues are fixed. I really have not had any issues thus far other then the optical drive no working sometime but i determined that was due to a specific brand of writable DVDs.

I await others experiences before updating. Running 10.10.1 on my 2007 MBP (had to after the hard drive got corrupted after i removed the 10.10 beta from the partition. Seems to run fine other then it killed my battery (ie went from 75% life to 2% life after the upgrade.

I did upgrade to 10.10.1 but it didn't resolve the graphic problem. The problem persist when transparency is turned ON. Turning transparency OFF still the fix for me. According to Adobe staff Apple is aware of this problem and they are working together to find a fix that is suppose to be available in 10.10.2

i just checked my apple care it expired the 8th of Dec 2014 should i update and if i have issues have apple fix it before the apple care expires?

2011 iMac 27 with the AMD Radeon HD 6770M 1025 MB failed when upgrading to Yosemite. I spent weeks thinking it was software. I had the same symptoms as others in this thread. I took it to an authorized Apple service center where the diagnostics immediately showed I had a failed graphics card. Apple is still honoring the replacement of these boards and agreed to replace the graphics card free of charge. Thanks Apple for supporting a product 2 1/2 years out of warranty.

Anyone out there have already installed the update 10.10.2 of Yosemite ? There was some resolution in the graphics problems?

RadocYoon:

See this Apple document about a recall of certain iMacs with the AMD Radeon HD 6970M graphic card: iMac (27-inch): AMD Radeon 6970M Video Card Replacement Program - Apple Support. It's good for 4 years from the date of purchase. I have the same model as you and went thru the recall process. They replaced the graphics card for free.

CarlosVB wrote:

Anyone out there have already installed the update 10.10.2 of Yosemite ? There was some resolution in the graphics problems?

Anyone running a beta would violate their NDA and the ToU here if they were to discuss it.

You're sort of correct. The Radeon cards are ALL good for 4 years. Mine is an AMD Radeon HD 6770M 512 MB. It WAS REPLACED, Yosemite 10.10 reinstalled, and everything has been better than good for about 3 weeks or so. They ALSO replaced my internal Superdrive, because when the tech had me on the phone, and we were trying to do an install from a Snow Leopard APPLE disc, the drive kept spitting it out. So, the tech gave me a CS Code that was "an approval to fix anything thats wrong-its basically a 30 day extension of the Applecare warranty." (My warranty had been gone for at least 4-6 months, but the number he gave 'reopened' the warranty for a period of 30 days).

The Best

I'm telling you that its the graphics card for me. The tech agreed, and I got the card replaced. (AND, it was an AMD Radeon HD 6770M 512 MB)!

The "red and green square" problem is not unique to Yosemite, by any means. This first appeared on my mid-2010 iMac i5 with Radeon HD 5750 machine over a year ago. I was running Snow Leopard at the time. In January 2014 my 1TB hard drive failed for the second time (the first time Apple fixed it in its recall program). After they put a new HD in the machine the red and green squares went away and I upgraded to Mountain Lion. The problem seemed "fixed" for about 6 months. Then, this summer the symptoms returned - red and green squares and recently a daily reboot to revive the system. Other posts on this forum suggested it is a heat related hardware problem in the video card, and a few have gone so far as to reflow the solder on the video card. Some suggested that turning off the sleep mode fixed the problem (it did seem to fix things for a month or so for me, but now the problem is worse than ever).

I want to install Yosemite but I'm hearing bad reports from this forum about it making the video problems worse. I really don't know what to do. Mid-2010 video card replacements are expensive, plus many reports indicate replacing the board is only a temporary fix. Right now, I'm so frustrated with this iMac that I've been tempted to sell it for parts and go back to the PC world...

Just experienced this these last few days. it has totally locked me out now.

Can't even boot in recovery mode.

I have a mid-2011 iMac, which fits the time that Apple says that the Graphics card is faulty.

Radeon HD 6970M

But why is it Yosemite that has shown up the error .

Should I replace the card or assume it is Yosemite ? But still I no longer have a bootable system.

just a grey screen 😢