Q: Greyish Smudge marks behind the glass screen.

Its really AMAZING how the Apple let this INCREDIBLE stupid and anoying problem to exists.

Anyway here is couple of guys from Serbia that are repairing LCDs and explaining the problem, with difusors.

http://www.youtube.com/watch?v=zGOw2ufBYaU
http://www.youtube.com/watch?v=3hM5MqLD9TE

Same problem here,
and it is not just behind the glass,it is behind the lcd,
impossible to clean...

This is really a design problem, and that must get public...


Anyone of you using a air humidifier?

No humidifier, occurrence is throughout the seasons, no cooking, no smoking, no candles, and good ventilation. My 46'' Samsung flat screen TV has no issues: It is unambiguously a design issue. Why it does not manifest as 100% manifest issue with all iMacs is a question mark but it does occur in an apparent large minority. I have a daughter about to enter college, and a girlfriend who I advocated Apple laptops who are both looking at desktops now- how can I advocate an iMac relative to the screen blemishes?

No humidifier here either, though I do have a friend with the same problem and she does use one sometimes.

I recently found another iMac owner affected by this problem who opened up his iMac to investigate. He posted pictures on a German discussion board, and in his case, it turned out to be dirt that had accumulated on the diffuser. He managed to simply wipe the spots away with a microfiber cloth. From the pictures he posted of the procedure, it appears that the panels in the Aluminum iMacs are not exactly tightly sealed. Both particles and moisture could potentially get in between the layers of the panel.

Can you post the Link to that Forum? Would like to See the Pictures!

Sure. The thread is located here:
http://www.macuser.de/forum/f7/imac-panel-defekt-385753/
The pictures can be found at the very end of the thread, though I think you may have to be a registered user to see them, not sure.

Interesting articles:

http://www.globaltimes.cn/www/english/sci-edu/china/2010-12/600774.html
http://www.derangedshaman.com/2010/12/11/imacs-suffer-from-irremovable-dirt-spot s-in-china-apple-says-country-is-to-dusty/

I brought this up a year ago and no one wanted to listen !!!

My mac went like this fater 3 months and Apple treated me like a piece of ****.

Fack them **** their products, I will never buy again from them.

I too have the same problem. Started manifesting itself a few months ago.
I use my iMac mainly for CAD work and play the odd game.
I do use Bootcamp some times but normally use Fusion to run the Windows apps that I need (Revit 2011, MS Office).
The smudge is located on the right hand side of the screen and extends from top to bottom,and it is only really apparent when the back ground is white. The mac gets warm but not too hot.
I have read quite a lot of discussions on the net re the smudges,so it isn't just a few isolated cases (It appears to be quite common).
I will be giving AppleCare a call in the morning. I will report back with their response.

I just found that my iMac has exactly the same problem (although not very serious). Sigh.....I have read many discussions including this one in the web. And start to question myself about the quality of Apple stuff (my iPod Touch 4G has experienced malfunction of peripheral buttons, which happened just around 1 month after purchased). Comparing to the past, Apple stuff is getting cheaper and more popular. We hope to see Apple is embracing the market more than before. However, the decrease in quality is in a way that consumers can't comprise with. I think Apple should take quality issues into serious account. iMac is not new product anymore, so there is no reason for it to be so immature!

I have called Apple for my case. And they just play me around with reseting PVRAM. Since the problem cannot be solved, they will send a technician to my home to follow the case. It is very likely to replace the LED panel, just don't want a refurbished panel with dead spots and more serious yellow tinge.

Should I go for Mac Pro when I decide to buy a new Mac? Or MacBook Pro? Until this moment, I still quite happy with Apples laptop.

I have to admit that I was rather hoping to never have to post in a Mac forum after so many problems with PC's..
I purchased an iMac (27" all the bells etc) in the hope of getting away from 'W' and had my fingers crossed that the yellow screen problem had been fixed.
Well I dont have the yellow screen, but these grey smuges / clouds have appeared over the last couple of months. Not there at first - then I thought they were on the photo of wallpaper. On loading a clean page (white) they are very obvious and annoying. This machine has seen zero use in 7 months as I was waiting for Office for Mac to appear before it becomes my main office computer. Now it has to go in for repair as soon as the program was loaded as writing docs with cluds over the page is simply not on.
Had to purchase Applecare to get it sorted as I did not fancy the hike to the nearest store (1.5 hours away and a pain to get the box to).
Not exactly happy about this I have to admit. They are not a cheap machine to buy new and I was hoping for a better experience. I wont be changing the other machines over in a hurry - tha'ts for certain.

Message was edited by: Steve2701

Message was edited by: Steve2701

I too have the same issues with a 27" iMac which is nearly a year old. I rang Apple as the machine is covered by Apple Care. The advisor was more than helpful, the machine is now booked in for repair at my nearest Apple Repair Centre. I did not get any hassle, no mention of enviromental issues etc. Whilst the issues around not having a machine whilst at repair etc are annoying, the machine (hopefully) will be repaired, presumably with a new display.
The display problems are much the same as those mentioned in this discussion, l do notice that when the machine is switched off, the display should be black, however, in the areas effected by the grey smudges (top left and right when turned on) - now show as a light grey (against the black) which vignettes at an angle down the screen.
I would also advise any user to switch the background to white to check, l always use a mid grey which is very similar in colour to the grey smudges - initially thought it was my eyesight!
Hope this helps.

Same problem from Hungary!
It seems this is a worldwide problem.

Shame Apple don't accept it.

I'm disappointed.

Same problem here from Slovenia, greyish marks on left top corner.
Tomorrow I will call a dealer and report how the problem was solved.

Same problem here in Italy, I just called Apple and tomorrow I have to go to dealer with my iMac 27 mid 2010.