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K_Rek Author

Level 1

5 points

Mid 2011 iMac Graphics Problems with Yosemite

I have a 21.5-inch, Mid 2011 iMac with an AMD Radeon HD 6770M 512 MB that is locking up on me constantly since installing Yosemite. Every time I reboot (which I have to do by pressing the power button on the back) it says that it has detected a graphics problem and do I want to report it. I have done that multiple times, but want to find out if anyone else here is having a similar problem. What appears on the screen are pixelated blocks in random areas and often the machine will work for maybe three or four minutes and then just lock up completely. It worked like a champ with 10.9.5 and previous, but 10.10 is wreaking havoc on my computer.

I have seen discussion threads about 27-inch iMacs that were recalled due to an AMD graphics chip problem, but haven't seen anything about the 21.5-inch machines. At the time, this was the highest-end card I could get in the 21.5-inch display.

The machine has 8GB of 1333 MHz DDR3 RAM.

iMac, OS X Yosemite (10.10)

Posted on Oct 21, 2014 5:58 AM

229 replies

Oct 29, 2014 7:29 PM in response to CouponPages

As it turns out... I didn't need long to crash it.

Moments after posting this, I launched Affinity Designer, which is a 64 bit graphics program that specifically claims to take advantage of the latest hardware.

After loading it, it IMMEDIATELY popped up a message saying there was a graphics card problem, and asked me to report it. As I did, the screen filled with the same random patterns and strange behaviors...

I checked the temperature of my CPU... it was only about 108 degrees F, and the fans were still running at full speed.

I immediately hit Command-Q, and quit Affinity Designer. Like magic, the screen returned to normal.

This leads me to agree that there may be some kind of driver issue. If I would guess, when nothing intensive is running, the system uses the Integrated Intel graphics, which seem to work fine. When something tries to take advantage of the AMD... that's when it will go nutty.

This begs the question... is there a way to disable the AMD GPU? That would confirm this, and allow us to have a functional system until a patch comes out.

My other thought is to simply boot from Mavericks from a Thunderbolt Drive, until they fix it. Any thoughts?

Oct 31, 2014 6:48 AM in response to K_Rek

I've got the exact same problem. Hoping they will actually fix this!

Oct 31, 2014 6:51 AM in response to K_Rek

Hi, I have the very same iMac, but not the issue whatsoever. Other issues related to software, yes, but not this.

dli23

Level 1

4 points

Oct 31, 2014 11:46 AM in response to K_Rek

I had the exact same issue with same machine. Called Apple, did a PRAM reset: OS X Mavericks: Reset your computer’s PRAM, then get a flashing screen. Reboot again, so far so good.

Where is the recall link? thx.

levimor

Level 1

0 points

Nov 3, 2014 12:34 AM in response to K_Rek

I tried the steps that Jean-Michel Dentand suggested, but unfortunately the graphics corruption problem is back with a vengeance!

gunnyst

Level 1

0 points

Nov 3, 2014 2:55 AM in response to K_Rek

Just an update from my side that "could" be more interesting than cleaning out other Startup Items.... Apple Support suggested the following to me:

(1) open disk utility and check & repair permissions

(2) delete the windowserver plist

(3) unplug my scanner and restart OS

While doing the first there where quite a few errors, mainly resulting from files owned by my Canon Scanner's drivers. Also there where quite a few permission issues on the OS kernel folders (yes, I do admit to have a DIY fusion drive installed and in order to enable TRIM I played around there, so could be an issue).

I'll be back with an update in a few days (or hours if things turn out not to have solved the issue)

Nov 3, 2014 3:06 AM in response to K_Rek

I've solved the problem reinstalling OS X Yosemite from Recovery Partition 10.10.

-Power off your Mac.

-Power on your Mac holding down Alt during the startup.

-Select Recovery 10.10.

-Open Disk Utility and erase your disk.

-Close Disk Utility.

-Select Install OS X.

-This will download the latest OS X versión and install it.

I don't know why but this have worked for me.

gunnyst

Level 1

0 points

Nov 3, 2014 7:20 AM in response to K_Rek

I just saw those graphical glitches again..... system didn't hang yet, but it was definitely nothing related to file system permissions or 3rd party hardware.... 😟

Nov 3, 2014 8:24 AM in response to gunnyst

Mine has been working fine for the last 24h after turning off transparency. I will report later if the issue comes back but for know my iMac is working fine for the first time after Yosemite upgrade.