Greyish Smudge marks behind the glass screen.

I too had this problem on my 2009 27" iMac.

Apple replaced the LCD shortly before my Applecare ran out. The problem has recurred and once again I have the dark smudges on the right side of my screen.

The problem has been identified as dust collecting between the lcd and the backlight diffuser. Several videos on Youtube show how this can be fixed by the owner, although it is not for the feint of heart.

If one doesn't mind taking apart their iMac, it is a DIY project. I will do mine in the next few days

Shame on Apple for a poor design.

Aloha,

I just read through several of these posts. I have had my 27" iMac since October 2010 without a hint of any problems. I don't use it every day since I have an iPad, so it is in sleep mode most of the time. Today I had several tasks to do that required a "real computer". After it was on for about 30 minutes I noticed a huge grey/fuzzy smudge over about 30% of the screen. My extended warranty expired 26 October 2013......so I thought "just my luck"! My husband is a retired IT specialist, so of course I expected him to miraculously 'fit it'. He did some trouble shooting and called Apple Support. The lady was very nice but not very helpful. However, as time went by with the computer on (not in sleep mode) the grey fuzzy smudge started getting smaller.

In one of the posts I noticed that a person from the Phillipines had the same problem and was told it was an environmental issue (humidity). Well, I have to totally agree. We live on the southeast area of the Big Island of Hawaii and have been getting a lot of rain the past week. My year old stainless steel LG refrigerator is also covered in haze due to the humidity.

So, I have to agree that it is environmental factors (humidity) and I'm very thankful the smudge is totally gone.

same problem for me 😟

I had this issue on my previous iMac (2009) twice and this one as well (2011) once, so did my Father in-law and also a couple at work. All different locations and all based in the UK which, to be honest, is not known for its humid climate.

Since Apple swapped out the screen un-questioning (didn't even power it on at the Apple store, just accepted my word and booked in a replacement screen) I haven't suffered the issue in 14 months of use.

Hi

I did clean my 2009 27™ iMac on the way it is descripted on the net.

I took it apart, and took apart the LCD unit, cleaned it two times. (ones dry next with cleaning liquide)

And no change it is just as it was before!!!!

Mine is probably not dust related but something else.

Does anyone has seen anything like that????

Thanks

rockjano

I can be added to the list of late 2012 iMac (bought it in June) owners with grey smudges. Bottom left and right corners behind the glass; the left side is a dark grey smudge resembling a large thumbprint, the right side is a collection of small oblongs. It appears to be gradually getting worse.

To be honest, I'm done with Apple. I love Mac OS and could never use Windows , but their hardware is overpriced, bearing in mind the components they use aren't special and are just as likely to go tits up. After years of defending Apple I fel like I've paid an absolute fortune for a pretty, slim box, and I feel like I should go back on everything I've said in their defence and admit that, yes, they're taking the **** with these machines.. I'm not sure what I'll do in the near-future (if it gets much worse I'll just buy another monitor to use with it) but this computer was a bloody s***load of saving so I'll make it last as long as possible.

I was terrified before buying this iMac as I had read a lot about the possibility of image retention, I have none of that (touch wood) but now this has appeared. For a 2000+ Euro machine this is not on. This is a proper moany post I know but on my income I had to plan saving for this about two and a half years in advance, so I think I'm entitled to have a bug up my arse about it.

I'm also in the Czech Republic. There are no real Apple stores here (only the online store) and they don't sell Apple Care because of pretty decent consumer rights. Really can't be bothered having someone fluff up replacing the screen (I took my Macbook Pro into the most reputable of the Apple resellers/repairers here to replace the logic board, they scratched the s**t out of the case somehow), only to have this problem resurface again, which according to many others, it will.

TL;DR Sadface.

You can't really compare an iMac monitor to an LG refrigerator. I live in a country with a very temperate climate and still have the grey smuding problmems with my screen.
I don't smoke and wouldn't say my home is particulary dusty or humid. So enviromental problems is not a factor.
Sorry to disappoint you, but the smudging on your screen will in all likeliness return some time in the future and get worse.
I'd lodge a complaint with Apple as soon as possible and start the long fight to have your monitor replaced.

I agree with you on the first paragraph. My iMac has been in two different climates and kept clean and dusted only to have this happen twice in just over a year. In my case it most defiantly is not moisture but a defect in the monitor or the manufacturing process. It did not "come & go" like others have experienced or try to say is the only thing happening. Mine started getting discolored and progressively got worse and wouldn't disappear if my computer was asleep or off. It was there if my computer had been turned off for a day and just turned on.

I don't agree with your second paragraph as I've had my iMac repaired both times no questions asked and within a week. I do have Apple Care though.

This is the part for me where MY paragraph 1 divided by MY experience in paragraph 2 equals my biggest issue with Apple "computer" right now. They fixed my computer, but before this I never had to get a computer purchased from them repaired.

What I am having here is NOT DUST RELATED!!

This is NOT accumulated dust, this is something else. I don't know I havent seen anything like it before...

rockjano

I did not wanted to yell at you I am sorry if I did I just wanted to emphases what I wrote You.

But to call somebody an idiot is not just rude it is also uncivilized

rockjano

I apologize for the end of my comment.

I find it uncivilized to use caps and yell at someone that is on their side and has just agreed with someone and validated their point.

John

And just so you know rockjano3:

I've taken my iMac to two different Apple Stores in two different cities to be repaired and at both places the Geniuses had no explanation and said: "I've never seen this before."

Sure they haven't…

I am in Hungary. We don't even have a real Apple Store here. :-( (apple just does not care of my country)

I took it to the service they told me that they know about the problem and Apple is willing to change the LCD unit even after the one year old guarantee period but only if the machine is not older than three years.

Mine was just about two month older :-)

So it really *****. No more iMac that is for sure, just maybe a mini and cheap 27" korean monitor from e-bay. Same screen than in the Cinema Display for a fraction of the price...

Or a Dell U2713HM.

I insist to the 2560x1440 pixel resolution.

The new mini's are good enough.

Or ...it might be a hackintosh machine...who knows :-)

I am also fed up with apple

rockjano

I took my 27" iMac into an Apple Store in the Houston area and they said the gray smudging is a "known issue" and they had the display replaced by the end of the day. They also replaced the GPU which was causing a totally different problem. Since my extended warranty ends next week, I'm taking the iMac in again tomorrow to have the optical drive replaced before it's too late. I've been very happy with the service I received.

PS. I've downloaded the Temperature Gauge Pro fan-control app to keep my system from frying itself in the future.

Man you are a lucky american... you don't how lucky you are all over there ... :-)

There are less fortunate places on earth :-)

I cannot do anything just accept the fact that my monitor looks ugly :-(