Mid 2011 iMac Graphics Problems with Yosemite

Be aware that Chrome is a resource hog (needs lots of RAM) and is made by Google which specializes in selling your private information. You can also try Firefox; I won't use a Google product on my Mac.

Hello all,

TLDR; Installing Java (Directly from Oracle), or the combination of steps taken including this Java installation, fixed this issue for me.

I'd like to start this whole post off with;

WOW!

I recently inherited an iMac that appeared to have issues similar to those noted here. Most GPU accelerated functions (Such as Videos, even flash media) would play completely corrupt. There were jagged colourful lines, and general 'media' corruption. These did not come out of the window that presented the issue. Even iTunes video content was a problem. It was really odd.

What upset me the most; the fact that the iMac ran FLAWLESSLY otherwise. And I mean flawlessly. Hardware Diagnostics returned without a hitch, applications load quickly - though I do not have any games or anything to test anything too fancy.

In my experience, most GPU failures are rather terminal. This seemed way too isolated, especially with everything else running, again; flawless.

I've been pulling my hair out, lack there of; trying to sort this out.

I can not 100% confirm the final fix, but it appears installing Java (Directly from Oracle) fixed this issue. I had tried all other settings, transparency, etc - with no luck. In my final stages of deciding; this machine will just have to remain a developer box - I installed Java. And everything is working. iTunes media content is working. Flash video's are working (Stock standard Safari).

Other steps I had tried during troubleshooting (In order, in case this is important);

Reinstall OSx, using both internet installation (Which installs Lion on this generation), and USB Yosemite installers.

Transparency settings

Colour Profiles (Including calibrating my own)

Power Settings - Though my model does not allow me to disable GPU switching, clearly.

Contacted Apple directly, and spoke to a technician (Chat) regarding the case.

Finally;

I googled "Apple Java Installer", which took me to the Apple KB page for their last release of Java for apple. Reading the notes, it stated; if you need the latest Java, download the Java for OSx directly from Oracle.

I downloaded, installed - And even without rebooting; 100% flawless.

Thanks to all that posted their notes on this issue. A few people suggested the Java install - and just as many said they tired, and failed. To those; Make sure you used the one from Oracle.

I'll post back if this deteriorates or returns. Otherwise - fingers crossed.

Another WOW from my side... I had Java 8 r25 installed. Just upgraded to version 8 r45, and I don't see the graphic glitches anymore...

If this was it, then a big thank you for the hint!

I also installed Java directly from Oracle and have not seen any artifacts in two days. I don't understand this potential fix but am glad for it. I will post back if anything changes.

I removed Java from my Mac to do the test, I went back to using Safari because I was using Chrome. I returned also with transparencies and after 12 hours of use the Mac is working normally without any error.

This issue is not limited to mid-2011. I have the same graphics failure after upgrading to Yosemite on my mid-2010, Model 6,2. I'm getting system crashes and reboots. Apparently Yosemite OS requires more of the GPU than it can handle.

I have followed this post for a long while as I was suffering with the same issues as everybody else. My mid 2011 27in iMac with 6770m (512mb) graphics has also been back to Apple twice, and been returned with no issue found... I have long believed this is software related, as it happens in remote desktop sessions also for me. Since Yosemite has been released I have rebuilt my machine from scratch numerous times to see if anything else would change, to which it has not. Reducing transparency has been the only thing that has helped along the way, but the issues still came up sometimes under intense graphics usage...

A week ago, my cousin came over with his early 2011 15in MBP, with the AMD 6550M discrete card in it, same symptoms but his was worse. Lucky, Apple actually have a recall for that particular machine so he is booked in for next week at an Apple store, however he asked if I could take a look as he needs something at least a little bit usable until next week. In the end, we backed up with time machine, and did an "Internet Restore" back to Lion. From there, went to the app store, downloaded Yosemite, and upgraded. His issues have vanished, not a single issue, the machine is booting as it should, no lag, no crashing when switching from internal to discrete graphics.

Applying the same logic, 3 days ago, I went to do an Internet Recovery on my iMac. Once the machine had booted into internet recovery (cmd + opt + R), i did a secure wipe of the hard drive (writing zeros), and then went to install Lion (10.7.5) over the internet. Once the machine had booted to its normal usage state, all looked good, no issues. From here, I went to the app store, and upgraded to Yosemite 10.10.4.

I have installed all of my apps, VMware, Chrome, Firefox, Office 2016, Toast, and I have not had a single glitch since. This is with transparency turned on! Perhaps worth giving it a try, i know it hasn't been mentioned here before...

I posed this in another thread but I wanted to share it here as well:

I'm dealing with the same issue. My computer is a 27" 2012 iMac with the 6970M graphics card. Everything was great until a month ago when randomly my iMac would flicker and go black. I have an external monitor hooked up to the device and this monitor always stays on when I'm experiencing the issue. Eventually the iMac screen comes back, sometimes its a few minutes other times its like an hour. Usually it goes black out of sleep when it does happen.

I took my computer to the store to have them look at it and they ran a bunch of test one of them being a VST test which it passed. The tech told me to have the faulty video card replaced it would have to fail the VST test. After she ran more test I got a chance to try and show her the issue. We booted the computer to my drive and put it to sleep, no issues. We put it to sleep a second time and sure enough the iMac did not come up, the external display come up fine. After a couple of minutes the iMac came back up which is what I've been experiencing.

So will see how things turn out but I'm getting concerned about the iMac passing the VST test even though the tech saw the issue first hand.

Thank you Captain DB! I have an iMac 27 mid-2011 w/2.7ghz i5 and 4GB ram. Of course an AMD Radeon HD 6770M 512MB, too. I rebuilt several times as I could tell it was software, as each time that I restarted the machine, the video was fine (or if I was in Recovery mode for example). I actually skipped the Lion update from 10.6.8 as it was unavailable from apple at the moment, and the machine was never updated to 10.7 at all. I went from 10.6 to 10.8 and got hung up on the java update from apple. So i just went right back to Yosemite and went all the way to 10.4.4. problem happened less, but would occur if I played a YouTube video.

After going to java.com and downloading the update that it automatically provides for you, I tried youtube again, and the problem was still there. After reboot, I walked out of the room and came back an hour later...youtube had been playing for the hour and the PROBLEM WAS GONE!!!!!

THANK YOU VERY MUCH FOR SHARING THIS SIMPLE FIX!!!!! So far so good. I never made it more than a few minutes before the problem came back. So after an hour, it is looking like downloading the JAVA update from java.com solved the problem!!!!!

Spoke too soon...the issue just came back.

actually...now it seems to be better. I found an earlier thread about how to empty certain cache folders under Macintosh HD/Library, and now it seems to be working...as Captain DB alluded to, you may need to try several things before it works. A combination of them appear to eventually wipe out the issue for many people.

If I experience this issue again, the next thing I will try is dealing with Flash, as I also noticed that another person was successful making changes to the flash config.

Anyway, thanks again Captain DB. Seems like I may be out of the woods for a while. Good luck to all! Odds are you have a perfectly fine machine that was tweaked when you installed Yosemite.

I have followed this thread for quite a while as I have a mid-2010 27" imac. This issues worsens dramatically every time any system software is updated, recently making my mac usable only for a few minutes after each reboot. For some reason, it seems to quite down each time after a week or so, with multiple hard resets and parameter ram resets. Upgrading my RAM also set me back a few weeks. I am no longer applying any system updates. I am also not using Safari as has been mentioned by others it seems to worsen the problem, which makes be believe it is a software issue.

I'm just wondering if any of you have tried using Disk Utility to repair disk permissions?

At one point I was experiencing the black out of my 27" mid-2011 and really had no clue what to do.

Errors that the console was throwing did not tell me what could be the problem.

After reading tens of topics and trying out all sorts of things, I read about the disk permissions.

I ran the utility and found some issues with the display driver. I repaired it and didn't experience any blackouts anymore!

However, after every OSX update I have to run the same utility again because it still occurs..

Hopefully this can help some of you guys..

I have a 2011 21.5 inch iMac that has the graphics problem. It was very subtle with Mavericks, but after installing Yosemite it became very obvious, locking up the whole computer at times. I have fought with this for almost a year now and I am hoping that El Capitan will make it better and not worse. I haven't heard of anyone else in the beta testers try it out on a machine that had this issue but hope that some people report their experiences before I upgrade.