Greyish Smudge marks behind the glass screen.

I had this with my current 2007 24: imac - I had two almost "stains" - AppleCare saved the day - I was out of he computer for almost a week BUT they replaced the screen and all has been fine for more than a year.

My 27" Core i7 iMac has this brown'ish blob in the top, middle-to-left, of the screen.

It looks exactly like some kind of burn mark...

I really hope I can get it exchanged for a new one... Though I will hate being without it for a couple of weeks!

Glad I came across this. I just today noticed a weird blemish behind my screen, 20" iMac purchased 9/07. I thought it was ON the screen at first, wiped it, and noticed it didn't go away. Looked closer, with a field of white displayed on the screen, and noticed it's indeed behind the front of the glass. This is really a let down as I use the computer a lot in full screen mode on both Photoshop and Aperture for processing photos. Oddly, or perhaps not, mine is in the lower-left of the screen...it's never hot down there. All the heat seems to be in the upper portion of the computer, so I have no idea why it's in the lower left. But regardless, it's there, and I'm now wondering what I'm supposed to do. This is way outside of warranty, but with that said, I also think it's outside of what Apple should consider acceptable. This thing isn't that old, at barely 2.5 years.

I have just found that my parents new 21.5 iMac has these greyish smudges on the upper left corner of the screen.

I am 100% sure that it is not the top of the glass because i have cleaned it and when it is turned off it looks perfect, shiny, no scratches, etc..

Restarted several times tried moving video/ images around it and it looks awful (at least to me, I guess parents haven't noticed it yet.) We have had it for about 3 months or so. I'll try to attach some pictures of how you can clearly see these blots even while booting, clearly a screen problem...

Message was edited by: rocket3500

http://i936.photobucket.com/albums/ad201/rocket3500/2010-03-03200359.jpg

http://i936.photobucket.com/albums/ad201/rocket3500/2010-03-03200404.jpg

http://i936.photobucket.com/albums/ad201/rocket3500/2010-03-03200439.jpg

That is basically what I had. To be 100% sure, do the ctlshift4 screen grab thing - grab a shot of the screen area - I bet it DOESN'T show up - it is something bad behind the lcd - need to get it replaced most likely.

Same problem, 27" Quad Imac. Purchased 2009, December 30th. Smudge is growing day by day, for me it is not acceptable to even consider taking off the glass myself. It is an Apple problem and Apple should resolve it. Either by taking it apart or by replacing the unit. I am pretty sure it is a manufacturing problem. The stripes are horizontal over the firs 30% of the screen (from the top) and there is a straight black line appearing on the right of the screen in a vertical position about 4cm wide.
It is 100% on the inside. As soon as I start up the machine and I get the grey apple screen with the logo it appears. Any light background shows the stains. Phoning Apple Care is a waste of time, they seem to have no clue what is wrong. They come up with outright dumb solutions like resetting the PRAM.

Machines are produced nowadays in China on the cheap and there lies the problem.

If Apple does not take care of it, I will consider throwing all Apple machines out. In the last year I have noticed that the Apple quality becomes worse by the day. I have not purchased one machine in the last two years that did not have some kind of problem. Sure, Apple normally takes care of it, but it is still a pain in the neck and every time I have to bring the machine in, wait for a week only to find out that the problems have not been resolved.

I have this same problem, i have had my 27inch imac since just before christmas i did not notice any marks until about a month ago probably due to the dark wallpaper i was using, i bought some iklear cleaning spray and have cleaned the front of the glass the back of the glass and the screen itself my marks appear to look like hand a print and it seems to be growing, look at the images below.

http://i1008.photobucket.com/albums/af202/jamesc79/imac%20problems/SAM_0161.jpg

http://i1008.photobucket.com/albums/af202/jamesc79/imac%20problems/SAM_0162.jpg

http://i1008.photobucket.com/albums/af202/jamesc79/imac%20problems/SAM_0163.jpg

Has anyone had any luck with apple replacing the screens ?

Same problem here. And this is a 27'' replacement of a 24'' that had similar problems that kept recurring after time post LCD and glass and fan replacements. I contacted Apple over a month ago and they said they didn't have the hardware (screens) available to do any replacements and would contact me when they did. The contact person is not returning my emails at this point though which is a first. I don't like looking at me through their eyes: they seem to think if these smudgy/burny/dirty smudges are continual they must be user-envirnment catalyzed. But I don't smoke, rarely boil water never-mind cook, it's not near a window, and it's well ventilated. I'm a long term mac guy that that feels doomed relative to this creepy screen curse.

I have a 24" iMAC from mid 2006 that has been working great. The HD went out a couple months ago and I had it replaced at the apple store. After I got the machine back I noticed some faint streaks running from the right middle to the middle lower of the screen. The tech at the apple store said it was burn in, but it wasn't there before the HD swap. It seems to be on the inside of the screen, is there a clear cover panel over the actual LCD screen, or is what you can touch the LCD. For all the world it looks like a smear left by a cleaning rag. Screen shot will not show it but I did take a photo of it. Anyone know what this might be. http://idisk.mac.com/silverxrider/Public/screen.JPG

Apple has agreed to change the LCD on this replacement iMac because of the "grey/smudgey/dirty/burny" looking stain on my screen as soon as the screen arrives at the company that does in home reparations in N.Y.C. Since I have a complete absence of environmental catalysts I am confused by the reemergence of this quality of stain (on differing locations) on the LCD. I've had multiple screen and computer changes when the screen replacement (and fan blower) have not rectified the problem (initially fixed) with longevity. Apple does stand behind the product with replacements but the problem sure leads me to a "redundancy" pessimism. d

I have the same problem with a 24" unit. I thought I was going crazy as I had never seen this before so i am glad I found this thread. I just created a support case and got a call from Apple support. They passed me on to a senior support staff who proceeded to give me the company line BS. They have to inspect it before they could authorize a repair. They are not admitting that this is a known issue. Obviously unfortunately there have not been enough cases of this reported. The Apple rep kept referring to the problem as a "cosmetic" issue.

Now, none of that is an unreasonable request, except for that fact that the closest authorized repair center is 150 miles away from me. So my only choice now is to make a 300 mile trip just to have some idiot look at it and go "Yup! Looks like the LCD needs to be replaced."

As someone who has been using Apple products since 1980, and acting as a consultant for 1000's of clients over the years, not to mention having purchased or used pretty much every single Mac model ever released out there, I am pretty disappointed by this response.

BTW:
They made a big stink about the fact that I mentioned that I had removed the front glass panel to inspect the problem. So, in case you are calling about this issue DO NOT ADMITT you have removed the glass! Apparently thy believe this can void the warranty.

Message was edited by: Shahin

Yes, it was really easy. I put the sucker on the glass just under the iSight camera, gave it a gentle pull and it came away very easily. Made sure I held it at the bottom just in case the suction gave out. Simple to put back as well 'cos the screen has guide pins which makes it easy to position it correctly.
Since cleaning it a couple of months ago it's still nice and clear and I can't detect any recurrence of the problem.

Hi
I was nervous before I tried it, but it proved to be very easy. You're right to be concerned that it would void your warranty - it will - but so long as you're careful it would be difficult to get it wrong. When I put the sucker on at the top and gave it a gentle pull it came away very easily. The only difficult bit was making sure you get rid of any streaks on the glass when you clean it with a lint free cloth.
If you do attempt it make sure you unplug the power first.

Could this be a condensation issue caused by room temperature?

If the room the iMac is in is cold when the iMac switches on, the iMac will heat up but the glass on the screen will still be at room temperature (think car windscreen when you put the heater on in the car and it's cold outside), condensation builds up on the inside of the windscreen, because the internal temperature is higher than the external temperature, the moisture in the hotter air condenses on the windscreen.

When it dries the windscreen is blotchy where the condensation dried.

This could be one of the environmental conditions Apple were talking about couldn't it?

I think this is a good theory. The stains I had could easily have been caused by a repeated sequence of condensation/bit of dust/dry out. As I said in an earlier post I bought the iMac second hand so I don't know the conditions it was used in for the first 10 months of its life. However I do know the conditions it's been used in since I bought it nearly three months ago and I'm pleased to say the stain hasn't returned (so far!).