Red and green square dots?

Same problem here, it may have just be a coincidence but mine started exactly when I upgraded to OSX 10.9.1. Luckily for me it comes up and I move a window around and it gets rid of them. I have LOVED this iMac since I got it in 2010. Guess it is telling me it is time for an upgrade also with me my MBP does not have this problem, even though I also upgraded it to the same OS at the same time. I do agree, 13 pages and there is more than one thread with this issue and yet nothing from Apple. I really do like Apple products better that Micrsoft but their customer support is ridiculous after your warentee period runs out.

Update on my AppleCare repair:

Got a call from the Apple store telling me that they went ahead and wiped the drive and installed a fresh OS X on it(after replacing the logic board and video card previously). Told me that they've tested it thoroughly and the problem has been resolved. I said great, would you mind opening up finder and scrolling for a few seconds because that's what i will do when i come to pick it up. The person on the phone told me they've tested it in many different ways and that the issue was completely gone. I said, ok. I stopped in last night to pick it up and asked them to set it up for me to test.

It booted up to the setup screen and right away i could see a few pink pixels(not squares). As i went thru the setup i could see weird things happening briefly. When i got to the desktop, i opened finder and there was immediately a problem. No pink squares this time, but all the icons were a jumble. Hard to explain without a screenshot, but they were a mess. Scrolling made it immediately apparent there was a major problem. The apple store employees that worked on it were aghast. They couldn't believe it. They said they did everything they could think of to reproduce this issue but nothing happened.

Now, they're just going to replace the system with a new one. Hurray! No idea what would have been done for me if this was not under AppleCare.

Thanks for the update, denmoff77.

Can you remind us what year, screen size, video card your iMac is?

I'm still holding out hope that Apple will take care of those of us whose Apple Care recently expired...

Sorry. I have the 27" iMac i7 2.93GHz, ATI Radeon HD 5750 1024MB.

I have 9 of these in a lab. Until today, i thought only one of them had this problem. I now see this happening on a second. Looks like another trip to the Apple Store.

Thanks, denmoff77.

2010 or 2011 iMacs?

Keep us up to date on how many of the other iMacs in your lab develop the problem.

mid 2010.

That's the same machine I have.

Maybe you stated this earlier... You must have been very close to an expired Apple Care when you first took your iMac into the Genius Bar?

"Now, they're just going to replace the system with a new one. Hurray! No idea what would have been done for me if this was not under AppleCare."

For those without AC, Sounds like $800 (previous post) for a critical rebuild and it's then pinned on Apple to get it right (90 days). I have a 2010 ATI 5750 as well; this simply reinforces the conclusion that Apple has no idea how to fix this problem except for a critical rebuild or a new machine replacement. Systemic in bith the hardware and software side.

We purchased 4 year AppleCare with this model.

smart man.

soulnational, are you considering paying the $800 for the rebuild?

In my case, my iMac is worth far more than $800, since other than this issue, it is a powerful, fully functional machine (minus thunderbolt technology).

If I exhausted all other channels with Apple for them to take full responsibility and then if I trusted that Apple would either fix it or replace it for $800, I think I would pay the $800, rather than junk the it and buy a new machine.

Yeah, I think so, I'm putting some cash aside. I have a 2.93 w/16gb RAM, it's a killer iMac, just a bit thicker than the new ones, otherwise, if this thing wasn't acting up, it'd be nearly on-par with the latest offering. Right now, I seem to be minimizing glitches with what I learned form others and some of my own experiences, my machine is ~85% running stable, so I'm holding out until maybe late summer if I can stretch it.

I will say this: I live 100 miles from the nearest Genius Bar, so, anyone in the ATI 5750 mid-2010 camp curious what our fix would be without Apple Care, I'm sure we'd all like to see additional quotes now that this issue is escalating with the Mavericks gen.

the update from my end is that installing the latest version of mavericks has solved all the of the issues. it's been about a week and i've havent had any display anomolies i experienced before updating

what i did ...

installed mavericks and updated every possible application - premiere, lightroom, photoshop, CUDA drivers / engine, bridge, all browsers and any other random applications that offered an update.

i deleted all old versions of creative cloud applications, cleared all browser caches and took a good look through libraries to clean out anything i was sure i could delete with bricking in my system.

final thoughts ...

i should have never given any weight to reviews in the app store. a) there's only 16000+ which is a miniscule % of users and only 3000 or so of those are negative ... a good number of compaints were simply that it took too long to download and install. my adivce .. if you're holding off like i was ... dont, instal today. in addition to solving my problem i actually like the os and it has restored a bit of faith in apple.

i suspect the reason this thread hasnt come up with a definitive solution is that lots of issues can manifest as pixel / display problems ... sw incompatability, any number of HW failures (cards, logic boards) dirt, overheating. so ... it's likley that the 50 or so particpaints on this thread actually have 10 different problems.

and finally, this isn't actually a pervasive problem for apple and 2011 iMacs - they sold about 17,000,000 in 2011 - about 1/2 of those in q3 & 4 ... this thread has only been viewed 10,000 times ... let's say that's 2500 unique viewers ... assume only 1 in 10 people experiencing this problem are motivated enough to research the issue and find this thread .... that's 25,000 users of out 17 million, even if it's 250,000 user that's still only 1.4% - not nearly a large enough problem consumer electronics company to get crazy over.

thanks for all the help with this ... hope you find a solution for your whatever's ailing your machine ... it does suck!

greggfromsf wrote:

the update from my end is that installing the latest version of mavericks has solved all the of the issues. it's been about a week and i've havent had any display anomolies i experienced before updating

what i did ...

installed mavericks and updated every possible application - premiere, lightroom, photoshop, CUDA drivers / engine, bridge, all browsers and any other random applications that offered an update.

i deleted all old versions of creative cloud applications, cleared all browser caches and took a good look through libraries to clean out anything i was sure i could delete with bricking in my system.

That's awesome to hear your symptoms were cured with Mavericks. The rest of us aren't benefiting from Apple's OS upgrades. And I think it's fair to say that your numbers are unfounded. For example, Apple has a recall in place with a sister display card to the 5750. There's clearly an issue with this gen iMacs. Just becuase your system is running nicely doesn't mean it's OK to write-off the systemic issues many are facing.