Q: Red and green square dots?

Agree regarding Windows through Bootcamp.  I have Windows 8 installed and see the same multicolored pixels even on the start menu.  Cannot comment on W7 but same issue.

Still waiting to get a cable from the 2010 to most recent iMac to test display mode.

I am having the same issue with my mid-2010 27" iMac and have been following this post for some time now.  Just thought I would throw my two cents worth in.....I have tried all the suggestions short of replacing and hardware and nothing seems to work....or more precisely.....they all seem to help but the problem always comes back.....the worst is definitely when the Mac has been asleep or idle for awhile.....rebooting used to help but not really anymore.....what I have found that seems to hold off the pixels the longest.....at least for me....is running Onyx....I repair the disk permissions and flush all the caches and then reboot.....that seems to help the most of what I have tried so far......

I have run in Safe Boot mode and don't seem to get the flashy pixels.....haven't tried booting in my Bootcamp partition yet either......

and of course my Applecare has expired!!!!!  UGH!!!!! 

There are so many who have this issue. I'm totally jealous of the person who posted that Apple gave them a new 27" iMac with Apple Care, since they couldn't figure out the problem.

https://discussions.apple.com/message/23625250#23625250

We must have some recourse other than to junk an otherwise perfectly good high end computer and spend over $2000 replacing it.

Can we organize somehow to get the attention of Apple?

That was me. The Apple Store replaced my video card and logic board, but the pink squares returned. They then wiped the hard drive and that created a new problem where the icons in the finder window became distorted when scrolling. That's when they agreed to replace the model.

About a month later, a second Mac of the same model(there are a total of 9 in a this computer lab) started having the same issue with the pink squares. I took it in to the Apple store and reminded them of the issue with the previous mac. This time they just wiped the hard drive and put a new Mavericks 10.9.2 on it and the issue did not present itself again. So, I spent about 20 minutes in the Apple store scrolling vigurously in the finder to try to reproduce the pink squares (probably looked like a mentally hadicapped individual to onlookers) but they did not reappear. So they closed the case on it. This was yesterday and i've just finished re-imaging the Mac today(it's a dual boot Mac). I haven't seen the pink squares come back, but i'm very skeptical that they're gone for good.

If they do return, i'll probably have to jump thru the same hoops again. Apple will wipe the drive and I'll have to hope that it doesn't "fix" the problem.

No, actually that was ME . (Follow the link.)

So I guess they've done it more than once, although my iMac's ONLY issue was the purple/green pixel problem. (Any time I took the computer in for this problem, or any other problem for that matter, I wiped the hard drive myself and install a virgin latest OS. That way they can't blame anything I've installed, and can't access my stuff.)

(Any time I took the computer in for this problem, or any other problem for that matter, I wiped the hard drive myself and install a virgin latest OS. That way they can't blame anything I've installed, and can't access my stuff.)

...which is a great idea we all should adhere to when dealing with Apple over this issue.

So about 2 weeks ago I finally bit the bullet and bought a new iMac because the freezing was getting worse to the point where i had to do a hard restart a few times per day. I plan on selling this brand new iMac BEFORE AppleCare expires.

Today I formatted the 2010 iMac that had the square glitches, and reinstalled the original Snow Leopard OS that came with it. After i had formatted, but before I had even started the Snow Leopard installation from the CD, I was seeing the square glitches already. Upon the first time it booted to the desktop, the glitches were filling the screen.

I plan on taking the old iMac in to see what my options are as far as repair. If it's only a few hundred $, I'll fix it then sell it.

The red and green square dot arts started to occur on my iMac 2009 i7 today morning.

- Both wireless keyboard and trackpad stopped working with this iMac so I couldn't even login to the desktop and delete some apps people mentioned in this post.

- Resetting PRAM/SMC = no luck.

- The red and green dots pattern varied everytime when rebooting my iMac.

Any suggestions?

The red 'dot' apple!

green dots on Apple! Can't go to the next login screen.

Sometimes the probress bar appeared which I've never seen before the red and square dot bug.

Wow, ok. I'm not getting anything like that.

I get random blocks like this that flash and disappear.

Anyone else getting ones like mine?

I was getting all that with my mid 2010 iMac.

Latest update. After a week of Apple having my iMac they called and said my logic board is failing and they will replace it with a new one. So after replacing the graphics card a month ago now they will replace the logic board. Hopefully this will solve the pixels.

I will keep you updated on the status once I get back my iMac (hopefully this week) and see if I get any pixels with the new logic board.

I, too, was perpetually finding these random flashing pixels... after my mid-2010 iMac 27" i5 began restarting itself, nightly.

Had the hard drive sleep set to "never", but the screen set to 15 minutes of inactivity.

Changed screen to "never", and the restarting seems to have ceased... as have the flashing pixels.

All began with upgrade to Mavericks.

Prior to changing the sleep settings, I was continually running utilities which either report "clean" or correct a smattering of minor permissions... following any crashes, system-self-restarts, freezes-and-manual-power-off-restarts.

Now, all seems to have stabilized: Will follow up with reports over time, to see if problem has resolved...

Citiboy & harrisny,

I had my video card replaced twice, logic board replaced once, memory totally switched out for new, and although everything seemed better after the card/board replacements, the dancing pixels always came back within a few weeks UNLESS I set the screen to NEVER sleep. But that's not a "fix." I also had the problem under the last three OS's, not just Mavericks. I would clone my internal hardrive, then secure erase it, and install whatever the most current OS is/was at the time. NOTHING would be added to that drive that wasn't installed by the Apple installer. I would use it for casual browsing, if at all. I wanted to be sure the screen problem existed on a fresh system, and it wasn't being caused by a system problem or other installed software on my drive. Eventually the pixels would return, even when starting from the fresh system drive. Mine eventually got the point that I regardless of which drive I started from, could absolutely prevent the anomalies by not letting the screen sleep, and absolutely cause the anomalies to start by waking the screen after sleep, and then opening FaceTime and PhotoBooth. It seems that causing the video card to "work harder" would cause the problems to start.

That sums it well what I've going through. Apple is replacing the logic board for free since the graphics card didn't help. If the issue comes back after they replace the logic board (probably will) then maybe I will get a new computer since they can't resolve this.

I'm having the same issue with my 27-inch, Mid 2011 AMD Radeon HD 6770M 512 MB and two displays the other is a ASUS PB278 connected with a display port cable. Both monitors have the “Red and green square dots” issue.

I found it really hard to search the web and find anything pages matching what I was finding. I bet lots of people have this problem.

Alright guys, it sounds silly but...

Since I set my dock to auto-hide I have not had any flashing blocks.

I'll keep you posted.