Greyish Smudge marks behind the glass screen.

The above photo is my hugest problem, this is how my computer looks, it's a real pain.

I just had the tech out but he wouldn't change the screen because he found one TINY insect in there, the very first as I've had screen replacements before and I've never come across anything dead or alive in there, having lived in three different places, also my last iMac was a G3 'the bubble' and it was put through crap, with constant moves and various living conditions, it's unusual that the G3 lasted seven years without a gliche, no screen issues and certainly no insects, good luck everybody, also the tech assured me that I wouldn't have any hard ware problems due to this. PROBLEM NOT SOLVED and so NOT happy.

Grace I had the issue in the photo and took the glass out and cleaned it easily, Thats different to the smudge marks IN the actual display

which I also have.

cheers

rob.

hello again

i would like to see everyone that is out of warranty how do they deal with this issue

the thing is..either you pay the big cost of replacing the panel or...try and clean it iside..and im nmot talking about the first glass on the imac im talking about the actual panel

has anyne done this?

i have seen a post showing how to do that..of cxourse this is for expoerience users

I've had two replacement iMacs and constant screen and glass replacements and it still comes back, it can't have anything to do with where I live because I've moved three times, mine is still under warranty so I haven't tried a DIY clean up yet.

Also Rob do you have a photo of yours that you could post on here?

I'm in Liverpool, UK and have had this exact problem with my Late 2009 21.5in iMac. Grey blotches in top left of screen, visible only on white background such as Photoshop. My business? Photographer and designer, so yes, this was a BIG issue. Took it to my Apple store after discussion on phone with Apple tech, and, in spite of it being three weeks out of warranty, they replaced the screen without quibble. Not a hint of any kind of disquiet at all.

It seems pretty clear to me that this is a design fault. One assumes that Apple occasionally read these fourms (or perhaps they've given up as they find too many posts and issues like these!)

I will now be monitoring my monitor very closely for any hint of a return to this fault. I've been told I have a 3 month warranty on the replacement part (yep, just 3 months for a £300 part!!) so I expect to be back there again soon. The upside? Apple Store Liverpool fixed my machine in 24 hours from reciept of part. Not bad, eh?

and this was for free?

we dont have an official apple store here in greece but we have resellers and they said i had to pay like 300 euros for a replacement

that is why i am thinking to doa DIY operation cos im out of warranty the last one and ahlf year ago,...

I think there's two key differences here - the length of time out of warranty and whether you went to an Apple Store or not. 300 euros is about the cost of the new screen that Apple gave me. Try my buddy in Liverpool for Apple parts: www.thebookyard.com

ill try and contact them again...300 euros is a lot of mioney for me at the moment

I have the same problem with my 27 inch Mac Desktop. Bought it in Dec of 2009. Past the manufactuers warranty. Called support. Nothing they can do. Was quoted big money to replace screen. The end result is that i will never purchase another Mac product again. It seems to be a global and known issue with this model and its screen. But apple wont recall because they offer a limited one year and extended warranty. Ive never had any issues with any of my previous Mac products and was always very happy with their quality. But... now it has been jaded.

I posted back in May this year about my experience with iMac 27" screen problems after having my third led panel fitted in about seven months. My third panel hasnt suffered at all from the same smudging and almost burned in black marking as the first two did. Both these panels had developed marking within four weeks which got steadily worse over time. I've been using my iMac almost constantly in the past ten weeks since panel three was fitted, I've checked the screen every few days and its as arctic white as the day it was fitted. Yay!

What I did notice and this may be of interest to other users who are contemplating using their apple care is that the third panel fitted to my iMac has a 5mm black border around its edge which the other screens didnt have (it makes the screen area slightly smaller but hardly noticeable on a 27inch screen) This suggests to me a different type or make of replacement panel has been fitted and I'm curious whether Apple may have a new supplier or are fitting new model iMac screens that dont suffer from smudging? I've had a look through the posts and havent noticed droves of 2011 model iMac users posting problems. Fingers crossed my iMac is well and truly fixed. It's a joy to use the full screen with my photography workflow again which is the main reason I purchased it in the first place. So far so good.

Interesting! Would you be able to post some photos of your new screen with this 5mm black border/bezel? I'd be very curious to see, thanks!

I have a 27" iMac since January and just recently discovered through a white background in Photoshop that it wasn't my screen that is dirty from dust, but a series of dust-like lines on both top left and right corners and some to the sides that are clearly on the LCD behind the glass. This is unbearable on such an expensive and professional machine.

Here's the unmodified photo from my Canon 7D:

And this is the same photo with the levels tweaked to clearly show the problem:

Setting aside the discussion over warranty and costs, is there any official explanation regarding what this is and why it happens?