Greyish Smudge marks behind the glass screen.

Another one here! 27 Inch 2009 iMac...

First time happened a few months after purchase and was replaced without question and now the second time they denied citing environmental damage. I appealed and Apple have agreed to replace the screen under apple care warranty.

If anyone has their claim rejected due to environmental damage just stand your ground and insist they fix the computer under warranty. Tell them its kept clean and dry, its not acceptable for an expensive machine to have this problem, countless similar cases reported on the internet etc. If they still aren't budging ask to speak to someone higher up.

Im guessing this will happen again, I wish there was something that could help prevent the problem. If it is dust, isn't there some kind of filter that could be placed over the vents. Heat?? I recommend installing SMC Fan Control - you can monitor the CPU temperature and also control the fan speed. Humidity?? Why doesn't this problem happen to other computer screens and TV's in my house?

With hundreds of cases each week worldwide the problem would be known to all senior Apple employees but I suspect they're trying to limit costs as a recall would cost them dearly.

Perhaps we should start a facebook group. With enough people and cases reported in one place, Apple may have to take notice. There are so many threads like this one on various internet forums, If they were all merged together it would carry greater weight!

Same here in L.A.

Bought thru amazon.com last July and noticed the marks about 2 weeks ago. I tried the white screen for a few hours & it didn't work. Then i stumbled upon this thread.

My phone tech support expired, but i'm still covered under the 1 year warranty. I am going to set up an appointment with my local Apple store and take it in for an eval. I hope they don't give me the "environmental" excuse. I will be prepared with info from this thread.

Thanks to everyone for sharing!

Me too. Got my iMac 27 inch Dec. 2009, started to see the gray marks last month. Called my Apple Care support line yesterday. No problem, he made an appointment for me to bring it in to my local Apple Store Just brought it to the Apple store today. No problem at all with them covering it under my Apple Care Plan. I did tell them about all of these discussions and that for some it happened again after the repair. My tech said he will make clear note of it and if it happens again after this repair it will be covered. New Screen will be over nighted sand installed tomorrow. No conversation of environmental issues came up at all. I'm in Colorado Springs (Manitou) and this is the first iMac they have seen come in for this issue. So for me I am satisfied with Apples response to this. I leave my Mac of 24/7 in a smoke free, very clean home office. I might start to shut it down when I'm not using it to see if this helps.

21.5" imac purchased uk April 2010.
Bought solely for photograph viewing and editing.
same problem
yellow rippled "watermarking" top left corner.
Replaced under warranty.
Apple said known problem, very quickly offered pick up and replacement.
Back with me after 5 days.
Good service, shame it happened in the first place.
Always kept in large ventilated darkened room.
I find it hard to believe it is environmental.

My concern is that it will happen again unless there is a design fix.
Has anyone with a replacement screen had a second failure?

I noticed "smudges" —almost looked like smoke— behind the glass of my 8 month old 27" iMac. Once I switched to a light background, it appeared all along the upper third of the display. I pulled the glass and found that the problem wasn't on the inside of the glass but behind the LCD. I took it to a nearby Apple store and they replaced the LCD. Took it in on Friday and had it back on Sunday. I'm definitely going to buy Apple Care for it before the warranty expires.

Two 24"er's here and on one they replaced the whole computer and 5 months later it came back. The other one started about 2 months ago after the applecare ran out. So this has been going on for 3 years. You would think they would figure it out by now.

Guangzhou, China - same issue here. Has progressively been getting worse since I bought it 6 months ago. Now at the stage where it's all over the screen (greyish marks - in some places looks like someone has run their fingers down the back of the LCD).

Just searched and found all these posts about the problem, so will be calling Apple Support today.

what a pita - especially for the cost of this high end gear!

Just an update from my previous post, as my machine had the grey smudge issue - rang Apple Care - took the machine (iMac 27" - one year old) to the authorised repair centre, new screen ordered on Wednesday this week, new screen fitted today (Friday) and now back at home. Very good screen, no banding, no yellow tinging, no grey misting (hopefully for ever!). First class service from both the Apple Care Tech guy and from the repair centre. Shame it happened in the first place, but the Apple Care service has been first class - thanks. Hope everyone is treated the same way.

I'm having similar problems but I'm also getting something strange
It 1st started with the grey blobs, which you can see against a white background
http://i52.tinypic.com/vo4l03.jpg

But It is starting to get some weird ripple effect on it when on grey backgrounds
http://i55.tinypic.com/2e156ie.jpg

Which is a real pain as it affects images that I am retouching as I can't tell whats scrren & what's image

Has anyone else had these ripples?

Cheers
Andy

UPDATE. Brought it in to the Apple Store last Thursday. They had it repaired by Friday night! No questions asked and they did tell me that if it happens again they will fix it or replace it under the Apple Care coverage. Way to go Apple. Oh and by the way this was a $600+ replacement/repair so if you don't have Apple Care yet and you are still eligible, GET IT!

An up date on mine.
AmSys collected as they said they would on the Thursday.
Had a text message Friday to say it had been assesed & spare part ordered.
Rang on Monday to say it would be delivered on Tueday - which it was at 10AM.
Screen has been replaced.
No problem with smudges, banding or yellowness - but I'll be keeping a close eye.
No hassle whatsoever from Apple, so I am impressed with that. Just wish it hadn't happened as it has dented confidence, and I'm uncertain as to if it will occur again. As others have said - Applecare is a must for these now in my view.
I am very impressed by the service of AmSys.

Having the same issue. Purchased Dec 2009. But I'm SOL because the warranty is up and no AppleCare. Researching DIY ways but not looking good. Seeing the amount of posts on this topic is incredible. Apple has a problem here and I hope they address it.

The exact same thing here in Greece. iMac 27" bought early summer 2010. I have not yet contacted Apple's Reseller (we do not have an Apple store in Athens) but i will, tomorrow morning, and will keep you posted on what happens.
In any case, it is a shame for Apple to have this same issue on iMac displays and not fix it for over a year now. Amazingly enough the first post on this thread is Jan 2010, one full year ago, and still no official answer on the matter at least to the best of my knowledge.
My problem is that as i see from older posts, even replacing the LCD will not fix it permanently. Can we keep changing the LCD's forever? I was planning on keeping my iMac for 5 years min. How exactly am I supposed to change my display every 3-6 months? Unbelievable...

Good luck to all of us with defective iMacs

iMAC 27. These grey smudge marks started to appear after only a month of use. Took it to the Genius bar and they were so shocked at the extent of the marks, they didn't even question the cause. Replaced the screen straight away. Had the new screen for 2 weeks and the marks are starting again. Clearly, it's not a problem with the screen but something inside the machine behind the screen that is the culprit. I could change the screen as many times as I like but the problem will always return. I'm so annoyed with this machine. I may just have to go back to PC.

Hey everyone,
I'm beginning to think that this has nothing to do with dust/dirt!
The metal casing around my screen gets quite hot!!! It is quite a lot hotter on the left side (where the marks are) compared to the right side!
I truly believe that these marks are from heat, and not dust!