Greyish Smudge marks behind the glass screen.

Hi. Well i purchased my iMac on April 2010, Greece.
After 4 months on the upper left corner a blurry spot appeared.
As days passed by this blur expanded in a larger area upper left and started on the upper right corner too.
This blur is obvious when i use a black backround or when the mac is powered off..it's like humidity.
Finally i had my monitor replaced for free as i had a warranty.
Now 2 months from the replacement i noticed that the blur spot on the up left corner has come back.
I'm sure that it is allready expanding and i will have to face the same situation. It's very ANNOYING to face such problems with Apple.
Anyway i don't know what to do now.
I even bought a dehumidifier to keep the humidity in reasonable percentages!
Here are 2 pictures of the problem, now in it's early stage of expand ...:
http://img824.imageshack.us/i/dsc00071xh.jpg/
http://img189.imageshack.us/i/dsc00072lsh.jpg/

<It's dust. I had the same thing. It's because the machine vents at the top, so some of it is forced around the display from the back and sticks to the glass. Got a couple of suction cups from iFixit and took a lint-free cloth to the inside of the glass. The glass is only held on with magnets.>

Mine wasn't dust and it wasn't on the glass. I pulled the glass only to find that the smudging was in or behind the LCD. I took it to the Apple retail store and they replaced the LCD panel.

Let me add my iMac story along with all the others, mine has a happy ending though ... or does it?

I purchased my iMac 27" in January 2009. I noticed the display issue (looked like water marks, and gray "bloches") starting in about March, and didn't do anything about it. Once my Optical Drive stopped working in May, I finally hooked up the Time Machine, backed it up, and brought it into Apple. They gave me no problem whatsoever with replacement of the parts. Turnaround time was about 3 days.

In September, the display issues came back. Once my Hard Drive crapped out in Mid December, I then brought it in to Apple for service. They once again gave me No Issues at all with replacing both parts. At this point i knew i needed to purchase AppleCare, but completely forgot about it. Mid January, i noticed the screen problems again.... OH CRAP i said... Let me see if im still covered! I learned that My warranty expired January 3rd 2011........ OH CRAP (other words were used this time)... I called Apple and explained the situation..... screen was replaced twice.... The woman transferred me to "2nd Tier" support, where a Gentleman said that I was still within my "90 Day" warranty from my replacement in Decemeber. WHEW i said. So i brought my imac ONCE AGAIN to the store, and they replaced it ----- With no issues (as usual)....

I got my computer back (3rd repair) and brought it home..... The computer WOULD NOT BOOT (had to use Safe Boot), The optical drive was TOAST, and the BRAND NEW REPLACEMENT SCREEN was much worse than when i brought it in. I was Furious!! I called the same person from the 2nd tier support back, and he told me he would have to Call the Apple Store and see what the actual repairs were. He called me back about 15 minutes later and said that they would replace the entire machine (keep in mind, i'm out of warranty by about 21 days) --- I was very surprised. I was sent a mailing label for the old computer to go back... and once the label was SCANNED in CT, they shipped the brand new 27" mac. I rec'd the new Mac today...

Now is this good news? It sure is.... but i sure hope that Apple has gotten their act in gear.......

This evening I picked up my repaired iMac after ten days - they replaced the LCD under warranty and cleaned the front glass. Everything looks great again! Of course, it remains to be seen whether the problem will reappear; but I suspect so because there appears not to be an air tight seal between the front glass and the LCD.

Same issue here (Romania).: iMac i7 27" bought in March 2010.
Grey horizontal traces on top right part of the screen after less than one year.
It is now under replacing procedure for the LCD, will take it back tomorrow.
No smokers in house, no humidifiers etc..
For me it started clearly after beginning to play games on it (WoW, Lotro, Dragon Age, etc) so it is clear for me the culprit is overhesting of the video card behind the screen.
I had exactly the same issue with a 2007 iMac aluminum 24", after 2 years of use. Same, it began when I started gaming on it.
Conclusion is clear for me: stick with a PC for gaming and use a Mac (preferably a laptop) for other tasks. It's unfortunate, but that's where we are today.

update: I got it back home yesterday
It took 2 weeks of delay instead of 48 hours, seems the queue for repairing was quite long (!!). I got it delivered home as I had the AppleCare coverage.

so, now seems repaired, they replaced the LCD screen, but I wonder how long it will last; I still have 2 years coverage, if it will repeat I will change it and may be sell it 2 week before the coverage will expire just to be on the safe side. But of course this undermine a lot my trust in the quality of the hardware and especially *on the quality of the design*, hence Apple cannot make such big mistake to:
- not foresee overheating
- not protect (filter) the air on the top
- not seal perfectly the screen from external "aggression"
- not listen to the problems and find solution as this is recurrent in YEARS!.

About the comment on gaming: indeed this suck a lot of resources and creat a lot of overheating, but also picture/video editing does it.
So I may suggest a coupple of hint for those who want to do it all and still be with Mac:
- Buy a desktop MAc + a screen. This will separate the CPU and so forth from the screen, probably eliminating all your problem, although this means loosing the practical (stilish) way of all-in-one on your desk and only one cable (one of the reason why I bouth it btw)
- shorter session of gaming, and more REAL jogging outside: *your health will benefit from it!*

have a nice day everybody, in a way I hope I will not have to write in this topic for a long time
😉

I bought a secondhand 17' iMac. It did not have any issues before. I've recently had to render some 3d models on it and now it has started to develop this same issue on the top left side of the screen.

What can i do... it seems to extend?!

Finally took the plunge and took my 27" iMac (bought 31st July 2010) in for this problem.It has been like this since October 2010.

Genius person quite concerned but didn't offer any particular reason as to why it was happening.
My grey, smudgy marks were on the top half of the screen and spread from the right, centre and towards the left side.

Agreed the glass would likely need cleaning but it may also be a problem with the LCD screen.

To rectify they have replaced LCD and glass screens. Also fitted a new optical drive as that was only reading CDs (wouldn't read DVDs at all)

Took in on Wednesday 16th and work was completed by 18th. Very pleased with service but concerned that this may re happen - no explanation

i am having the same issue with blemishes on the left upper portion of my screen, brought it down to apple and they tell me its an environmental issue? apparently no being that there is more than one person with this same issue! Apple store wanted to charge me but after causing a scene in the store there going to fix it for free! Thats just great! i bought this computer because i thought that they would have excellent customer service, wrong apples customer service blows!! I shouldnt have to get worked up about this in order for them to fix an on going issue with there computers!

I took the glass off which was easier than I expected. I cleaned both the glass and the LCD screen and there is a minor improvement, so my question is can I use some kind of solvent on the LCD screen without damaging it?

I have a theory: when you remove the glass from the front of an imac you will see that a small amount of grease covers the magnets that hold the glass on (it is probably there to ensure a dust proof seal). My theory is that when the computers are assembled some of this grease is accidentally transferred to the LCD screen by the assembler. Then after a period of time the heat from the screen cooks the grease to give the stains that afflict so many of us. I am saying this because I cleaned my LCD screen and although the stains are still there they are less evident.

Hello,

I fixed the black spots/smudges/dust inside the display issue.

Here is how http://forums.macrumors.com/showthread.php?p=11976152&posted=1#post11976152

It is actually just dust between the backlight and the display panel glass and you can fix it!

Oggy

Message was edited by: Controllo

I seem to be having a similar problem as most people here, grayish smudges on the top left hand part of the screen. And I'm pretty sure it's not the glass as you can see in the picture below.

http://dl-web.dropbox.com/get/iMac%20scherm/Photo%20jan.%2023%2C%2023%2001%2045. jpg?w=1d5128b7

Is this covered by the one year standard warranty? I just bought my iMac in october 2010.
Recently I've also begun to notice a line on the right hand side of the screen, but contrary to the smudges it's not visible all the time. It only seems to appear after the screen has been on for a while, could be heat related? Does this sound familiar to anyone?

I have an intel imac from 2006 (thus, no glass front).

I've had this issue twice now. Once within the first year, and the screen was swapped. Now, over the course of the last 2 years, the problem is back (and now it starts to be much more visable).

I've two blotches, one in the bottom left and one in the top right.

Being out of warranty, I don't suppose they will repair it, which pi$$es me off as this is obviously a design issue. CLASS ACTION lawsuit anyone?!!?

I will call them, just in case, of course... 🙂

Same bug here .... 27 inch 2010 my first and last Mac but I will buy the Ipad2 🙂

3 weeks for réparation, got it back, its nice but still getting hot.

I'm scared but do you think I can let it powered up more than 12 hrs???

Even in sleep mode the comptuter get hot ... My Mac is a 2000$ Itunes and I'm scared to leeve it powered up

Antoine