Mid 2011 iMac Graphics Problems with Yosemite

Actually my Mac has a problem with the X Yosemite. My machine gives no failure in the picture, just hangs. My Radeon HD 6770M card is not in the replacement program, and there is no problem in it. I did the tests with the Mavericks and did not show any problem. My problem is identical to K_Rek of the problem and Apple does nothing to solve. I live in Brazil and I paid much a machine that today gives me many problems.

I experienced the same, bizarre pixellation problems with my mid 2011 27" iMac after installing Yosemite 2 days ago. After several reboots, it seems to be quieting down. I took the iMac to the local Apple store today and they ran diagnostics on the graphics card (AMD Radeon HD 6970M 1024 MB) and HD, and both were OK. Since the problem wasn't actively happening after an hour at the store, they said there was nothing more to do except leave it there for longer tests over several days, which I declined for now.

I'm wondering if anyone has heard any follow up from Apple about this?

After reading all the posts above, it sounds like it is a Yosemite problem, and (once again) no hardware problems were found by the Apple genius bar fellow. Is that the consensus?

I had these exact symptoms, but then they morphed into frequent kernel panics. I hadn't seen the confetti pixels in awhile, but the Genius at the Apple Store suspected that the issues were related. Anyway, they replaced the video card and it seems okay. I've only had it back a day, so we'll have to see if that did anything.

I'll provide a status update in a day or two to let you all know if that did the trick.

So far no issues with my 21.5" 2.7 ghz model so far no issues with 10.10.1. Don't have issues even with transparency turned on have off cause I like it better that way. mine was built dec 2011 bout dec 2011 as apple refurb. The unit shipped with 10.7 and never ran 10.6 would be interested if the unit having issues are the ones shipped with 10.6 or 10.7 installed? Wonders if 10.6 parts still left behind when updated. I think the latter mid 2011 units were shipped after the the 27" video card issues. Wonders if the later units got a fixed video card?

I'm having the same issue. Same iMac. It has graphics problems and freezes/reboots once a week. Sometimes twice a week.

I am running the latest 10.10.1 and will not believe anything about reboots or fresh installs.

Seriously. Since when did OS X become Windows 98?

This is really sad because the issues are making me wish I never upgraded to Yosemite and have even caused me to think about switching to Windows. (ick). It's definitely caused me to question the future of Apple 😟

This seems to be commonplace though. I can't run the Xbox One in normal mode (always on) without it having to be hard rebooted (holding power for 4 seconds) every day or so.

I don't know if it's the rush to get stuff out the door but Apple you really need to refocus on quality.

I don't foresee this getting fixed in the near future. We've seen the first update of Yosemite, and a major update to iOS 8, and all the annoying issues I have still persist unchanged. And they're like complete deal breakers. like they stop you from doing ANYTHING and you have to force close the app or there really is no workaround (iOS8) or the system freezes, crashes or reboots itself. (Yosemite)

The other thing I've noticed is that it will spontaneously just go black and then go back to the login screen, but it acts as if it rebooted.

Many of these issues don't happen to me on my Macbook Pro at work, although my computer at work just had a lovely issue. Trying to reboot and then it just sat there, opening any app quickly bringing up a "XX app cancelled shutdown. Try again?" and immediately disappeared with Try again being automatically clicked.. So I was unable to open up Terminal to force shutdown. All the apps seemed to close down but when I went to the force close window, I saw ALL MY APPS were still running. When I selected all of them and clicked Force Close only then did it reboot.

I really hope someone from Apple sees this thread and they fix it in the near future. I've never seen so many issues in a Mac OS. Ever. Weekly kernel panics are unheard of.

I Not seen any of these issues but I have seen issues if u do not uninstall the beta properly had issue with bets on MBP forcing me to upgrade to 10.10 as the removing the beta corrupted. 10.9 but I had little issues with 10.10 some issues I had with 10.9 are now gone. I have for year shut off all energy saving things like hard drive sleep screen sleep all just non sense to use as they I think damage your computer even more. I turn it on when I use it and turn it off when I

eave the house or go to bed. Live in apartment complex so never know during the day if they will cut power to fix something so to prevent power surges or sudden shutdowns I turn things off. So my computer gets started and shut down every day. I never left it on for more then 30 hours since I got it. Maybe shutting it down at night will save on ware and tare of the hardware. Making sure the computer is well ventilated helps as well. Even in sleep mode the computer puts put heat prolonged heat will cause damage. Interested to see if these problems are only happening to people who never shut there computers down.

you're apple 'genius' was NO genius! Call 1-800-my-apple, tell them that you believe the card is damaged, and since Radeon cards (mine is the 6770) are warranted for FOUR years, apple has been replacing them. Go back through this board, and the other board talking about pixelation, and count how many folks are wiping, reinstalling, trying fixes that 'sorta' work for a while, and then count those who have had the Radeon cards replaced. I've had (knock) ZERO problems since my May 2011 27" iMac had the card replaced a couple of months ago.

I never installed the beta. I don't install betas. I am uncertain whether the OP actually did that.

By the way, just to clarify, I rarely experience ANY actual visible graphics glitches.. just freezes and then it says "A graphics problem has occured."

hi everybody, i'm having the same F G problem !

i'm on MacBookPro 17"

Yosemite 10.10.1 (14B25)

2.4 GHz Intel Core i7

16 GB 1600 MHz DDR3

Intel HD Graphics 3000 512 MB

AMD Radeon HD 6770M

so after made this update my mac was with blue screen, grey screen too ... there were times I was able to boot.. and the problem was when the system switched the video card. Im off warranty, went in a tech and he changed the thermal paste he told made some BGA on the video chip. ok

after one week crash again.. I made today a line command boot and disable the AMD extensions .. as I saw on a youtube video .. so now i just don't now if I have to buy another video chip or if are some update to made ...

I contacted the folks at Apple for the fifth time and they instructed me to take a test that would be as follows, create a new user and do some tests to see if the problem happens. Did some testing, I forced the machine and no problem occurred in this test. Every time I reinstalled Yosemite I sought my time machine backup, will be that this can be a program or corrupted file that forces the machine and gives this problem? I did a test today, on my own, which is using a program that measures the performance of the CPU and OpenGL (the CINEBENCH), did the tests, forced the most of my plate and no problems were detected. In all tests I realized, I concluded that there is some specific file that causes the problem happens, 90% of the times it happens when I use Safari and the other 10% when using Adobe Photoshop. Does it really was a problem in the video card driver this error occur every time that was used at full power? I will return to my Windows user time and will format the machine and begin everything from scratch. Once you get the results I warned here.

I've got an iMac (27-inch, Mid 2011) 3.4 GHz Intel Core i7 with an AMD Radeon HD 6970M 1024 MB graphics card.

I was having the strange confetti-like pixilation issues as described elsewhere in this topic. After the original issue showed up, another issue soon appeared where I was having kernel panics every 10 minutes or so. The iMac was still covered under AppleCare, so I took it in and Apple replaced the graphics card. Took it home with a fresh install of Yosemite and restored from Time Machine. I immediately experienced the same kernel panics.

I had read somewhere that RAM was a likely suspect in these sorts of crashes. I removed the RAM modules from 2 slots and left the other 2 in there...with the idea that I would test them as pairs. Once I removed the first pair and restarted, the problem disappeared. I'll be replacing those 2 modules as soon as I can. The memory was purchased at Crucial, so it was fairly inexpensive.

Troubleshooting your RAM is worth looking into if you're not finding a resolution to this Yosemite/iMac issue. Even the guy at the genius bar said it wasn't the RAM when he ran diagnostics on it.

Good luck people.

The only problem I have with the idea that it might be the RAM is that I didn't have any issues whatsoever until I got Yosemite.

The issue is with the OS and this particular model Mac. I mean it is so uncanny that I find another person online that has the EXACT same issues I do with the EXACT same model iMac, when everyone is like "I don't have any of those issues" and I, too, at work have a Macbook Pro and don't have any of those issues.

I agree, said it all.

Yup, I had the same hesitance for the very reasons you state. Exact same iMac model and exact same issues. I also have a MacBook Pro both at home and work without these issues. I also read every post here and came to the same conclusion that Yosemite + this iMac = crap.

Of course, I did read something about bad RAM being related to kernel panics, but it seemed unlikely so I disregarded it. The arrival of all these issues at the same time of my Yosemite upgrade seemed too coincidental. But alas, after 4 weekends of wasted effort, I tried the RAM thing as a last ditch effort. Regardless of how I felt about the idea, it actually solved the issue for me.

Not saying your RAM is bad, but I wish someone had pointed my in that direction before I wasted so much time on Apple Store visits, wiping my system, reading these forums, etc. I was seriously ready to smash this thing into tiny pieces and just spring for a shiny new 5K model. 🙂

I agree as well