Red and green square dots?

It probably also doesn't hurt that this began right after your care expired and you had a history of them looking, mine waited until a full 2 years after Apple care expired. They had no interest in fixing it no matter how nice I was. Baking the card does work, and has been done with graphics cards outside of the Apple universe for quite some time. It also can fix broken XBOX 360s with some red rings of death. When all else fails you either have to spend money or bake your card. Try baking first.

Just wanted to give one more thumbs up to the baking solution. I had green and red squares appear randomly on my screen when the computer was cold. I read the 33 pages of comments here thankfully before taking my way-out-of-warranty 2010 27' iMac to the apple store. I pulled out the graphics card (ATI Radeon HD 5750 1024 MB), baked it at 385F for 7 minutes, applied new thermal compound on the head sink, popped it back in, went ahead and upgraded HDD to SSD while I was in there 🙂, put it back together, and it works beautifully. Not a colored square in sight, cold or hot. Thanks to those who suggested the idea.

As a side note, before I baked the card, I verified that the cold was the problem by downloading a program called NovaBench. This program bench tests several aspects of the computer including the GPU. Stressing these components warms them up, and indeed after starting up a cold mac (with colored squares) and running the test a few times, the artifacts stopped. Maybe that would be an acceptable interim solution for some. I just baked mine because I wanted to go in there for the SSD upgrade anyway.

The same problem, colored dots and squares, 2010, Radeon HD 5750 1Gb.

Problem first arrived today after installing 10.10.2 service pack, never seen before.

Crying... 😟

Is there any "ready-to-use solution" for this problem?..

Exactly the same issue here on 2010, Radeon HD 5750 1GB system after updating to 10.10.2. Pink squares and graphical corruption. Thought perhaps graphics card was on its way out but seems too coincidental having read your post.

These threads are loaded with people who loaded mavericks, updates after mavericks, Yosemite, 10.10.2 etc.... It's most likely your video card. It's just possible that it had time to cool while doing the update.

Yesterday i "downgraded" my Yosemite 10.10.2 to Mavericks 10.9.6 with a USB-recovery, and the problem solved.

Now i have perfectly working Mac under any videocard load.

Jochta, try the same. I think Yosemite 10.10.2 is just underdone.

Most likely it will be back.

Some day it will happen, i'm sure.

But not because of glitchy Yosemite 10.10.2.

And now reason for me is clear.

But you gave me a good advice - it's time to sell my Mac 🙂

I'm reading through this thread and I caught your location. I'm at SDSU trying to diagnose the same problem for a librarian here on campus. Frustrating! I'll keep reading to get caught up with events here...

-Steve

I'm joining the list, just upgraded to Yosemite 10.10.2 and there are the red en green square dots 😟

PS the funny trick by using your mouse to "click-select-drag" over the area showing the red en green square dots seems to get rid of them for over half an hour now...

For me the problem became worse than annoying colored boxes on my screen. Eventually the system would freeze up completely. But it did start out as just annoying.

I had the same problem. First "click-select-drag", after some iterations - freeze 4ever.

===

Downgraded to Mavericks, and had the same problem (squares) twice, but disappeared after 'click-dragging', and no freezes.

Also i'm trying to understand the reason of the problem.

And thats what i noticed:

- I always have this problem on 'cold' iMac - 5 minutes after it starts;

- All the squares appear over background (not over program/browser windows);

- All the squares disappear after click-dragging, and do not appear when iMac is 'warm' (after 5 minutes);

- Any video stress-tests. benchmarks - the system goes slow, but NO squares.

- Never seen dots&squares on parallels Windows7 mode.

Is it just some kind of phantasmagoria ? 🙂

No this is a problem with a defect in the graphics card. All the baking you see mentioned above in the thread effectively re-flows the solder. The hypothesis is that the solder has developed miniature breaks that are agitated by contraction when cold. I can say with 100% certainty that everything I did up until baking my card did not work. It was my last ditch effort, and was completely successful. It's been a couple months now and I have not seen a single artifact, and have not had a single freeze up. If you have access to a heat gun you can get the same results with targeted heat.

I have the same issue with the large dots. It only happens when I have a video selected in the finder. When I have a .MOV, .MP4, etc. selected in the finder, both of my displays are covered with these large dots. If I click away from the video file, the dots will remain until the display refreshes by me clicking on the application window beneath the dots, etc. If I select the video file again, the dots all come back. I haven't seen a solution in this thread (I've read a lot of the posts, but not all). I have a 2010 iMac, 27 inch, 2.8 GHz Core i5 running 10.7.5. Just started happening in the past few months. I've seen a few posts about uninstalling Chrome to fix it. Does that work? And if so, why? And doesn't seem like a long term solution since I need to test in chrome.

I've had a bad time with the red and green blocks for a while.

The last two days where a **** with constant crashes and reboots.

Desperate to get the problem solved I baked my Ati Radeon 5870

What a ridiculous idea, really!

It has been an hour after the baking and the squares have not appeared yet.

So my baking method is the same as the others; 200 degree Celsius, preheat oven, then exactly 7 minutes in the oven with all the plastic parts facing down. Did not repaste the heat sink or whatever. I let it cool for a while and reinstalled it in the MacPro 2009

I hope I will not have to post in this discussion all in tears... fingers crossed.

PS do they have ovens behind the genius bar?