Forum Question: Dark spot/stain on iMac screen

Dear Gary
It is certainly quite annoying having myself spend a large amount of money on a new computer, while trying to “reach” the renowned quality of Apple’s products & technology (I’m a former PC user), just to find out that the whole thing maybe is just not so true.
I wouldn’t be such a criticizer if it wasn’t for my 16-month-old 21.5-inch iMac, which I have already twice repaired (fortunately while still under warranty) for a bothersome dark stain on the upper left corner of the screen. But, as I have recently noticed, the “dark stranger” seems to have hit for the third time.
I can in no way accept that I’m that unlucky & I’ve started believing that either all the screens share a certain constructional defect, or the internal design of the hardware (position of the fan or the ventilation channels or something generally related with heat abduction) causes the screens to show after some time this specific stain. Not forgetting of course that the same problem has appeared to iMacs exhibited in Apple retail shops.
The answer of the Apple technicians when asked, was rather vague & unclear (“dust, moisture, cigarette smoking” while I’m not a smoker & the computer is working in an ideal environment & other unbelievable nonsense were the possible answers they gave me). Finally, they made me believe that they just don’t know or don’t want to share with me the real cause of this problem. A problem that doesn’t seem to appear to much cheaper computers! It’s really disappointing…
Knowing that many other iMac users have come up against the same problem, I would like to ask for your opinion & your thoughts on this.
Kind regards

Comments: 18 Responses to “Dark spot/stain on iMac screen”

    4/18/11 @ 7:09 pm

    I’m not sure what sort of opinion I can give you on this. I’ve never heard of a dark spot issue with 2010 iMacs. What did they do to fix it? I would suspect they have fixed the symptom and not the solution. For instance, it could be something wrong with your case that causes this to happen with any screen installed. By replacing the screen, the problem just comes up again. Or something like that.
    All technology manufacturers are faced with this. We demand cheap products and updates every year. There’s competition and they have to make products quickly and cheaply to stay competitive. That’s true of Apple, Dell, Sony, Toyota, etc.
    Apple has a great brand name. But they are not magicians. They get the parts from the same places as other computer makers. They use the same factories as others to assemble them.
    They probably could make iMacs with all parts from Apple-controlled factories, using highly-skilled workers, and putting them through rigorous quality tests. So how well do you think a $5,000 iMac would sell?
    Do you think that everyone who walks out of the Apple Store with an iMac has this dark spot problem? No, of course not. Problems that plague as little as 1% of units usually make huge headlines on Mac news sites.
    If you don’t think that cheaper computers have problems, then you are wrong. I’ve bought enough $500 PCs in my day to tell you they do.
    So I’m not sure what you want me to say about this. You got a problem Mac. I know others that have had problem Macs in the past. I know others that have had problem PCs in the past. Problem TVs. Problem cars. It happens.

    4/19/11 @ 1:52 am

    Thank you so much for your immediate answer.
    Your comments on the contemporary product development & marketing tactics of computer manufacturers are absolutely right but how can you explain the fact that I have read for the same symptom from users around the globe? Or the fact that this stain problem exists in iMacs exhibited in an Apple retail shop in my city (I live in Thessaloniki, Greece)? Doesn’t this mean that there are specific batches of products with a certain defect? I believe that the problem is much more common that you think, as the stain is most of the times very faint to see & it’s visible only 2-3 months later & if the specific quadrant of the screen shows a light-colored window.
    It would be unfair for Apple if I didn’t mention that I really enjoy working with my iMac & embrace Apple’s perspective on how an OS should look & cooperate with the user. But it’s really a pity having these cursed stains ruin your expectations & respect for a renowned brand.
    Thanks again for your precious time & the help you offer to Mac users through your web-site. It would be great if you would let me know anything new you might learn regarding my problem.

    Best regards

    4/19/11 @ 9:39 am

    a friend had this problem in another way, turns out that the problematic area of the screen was facing an entrance and he living in an oceanside part of florida encountered a lot of humidity every time the kids opened the doors and the A/C turned on to cool the room again, but his computer was already cooled so the warm humid air interacted with the coolest spot on the case and it caused moisture/condensation stain on the screen. This is more common than you think.

      4/19/11 @ 9:43 am

      Martin’s comment fits with what I said earlier. What are the chances of you getting three bad LCDs in a row? Virtually nil. So the bad LCD is a symptom, not the problem.
      It is like when you have one tire on your car wear differently than others. Replace the tire or rotate them and the same thing happens. The tire isn’t the problem. Something else in the car is causing it to wear differently.
      The “humidity interacting with the coolest spot” theory makes some sense. Or, if it is not that, then something else leading to the symptom.
      Sorry I can’t offer a solution, though.

      4/20/11 @ 12:09 am

      So, as someone could hilariously say, “iMac is so “cool” that even warm humid air trapped behind its screen glass condenses, creating a dark stain-effect.” Well, it’s a theory based on a natural law, no one can deny it. But, on the other hand, is really the front surface of the screen (not the glass) cool enough, during iMac being turned-on, for humid air to condense & cause the whole thing? And why only on this specific area of the display? And also why does this small quantity of humid air not re-evaporate after some time of operation? As you may see, there are a lot of questions emerging and I personally believe that Apple should actually look into this matter. As Gary previously mentioned, they are not magicians but they certainly have the technical knowledge to solve problems like this. For me this is essential for keeping up with their own reputation as a brand.
      Anyway, thanks a lot for your suggestion. Gary, I rely on the power of your forum & the information it can gather, to have a possible long-time solution of my stain-problem…

    Hugh Fraser
    4/21/11 @ 9:41 am

    Hi Jim,
    I also have this same issue, it appears to me as though it is like screen burn, the type of thing screen savers are supposed to help with, may be you and me are the only two who has this but I would very much doubt that, oh by the way, my machine is around the six month old.

    Just tried taking a screen shot, it’s weird, it doesn’t show up on the screen shot.

      4/22/11 @ 3:02 am

      Hi Hugh

      It seems that the “dark stain” effect goes around the world. I can really give no explanation for our problem, but the fact that it every time appears in almost the same area of the screen, makes me unwilling to believe it has to do with a “lazy” screensaver. I also tried to check the stain with a full-screen snapshot (“command-shift-3”), as you told me, but the stain remained at his place. As I have mentioned before, the screen must show a light-colored window in that specific area for the stain to become clearly visible by a careful observer. I think that’s the main reason for any user not having noticed the problem yet. I would suggest that you lose no time and have your screen serviced as soon as possible (before the “one-year-warranty” expires). I am really curious to learn from you what the technicians will say about the problem. I wish you to have it solved once and for all. Looking forward to hearing from you…


    4/24/11 @ 9:56 pm

    I have the same problem as Jim. same spot as well. At the top left corner. Worst thing I just bought it last month. only used it for one month till now. I am in New Jerey, USA. Will go back to Apple Store next week to check.

      4/25/11 @ 8:06 am

      Dear Diane

      I’m very sorry to hear about your “stain” problem in your almost new iMac. I really hope that after visiting your local Apple store, you receive a suitable answer & a permanent solution to this nuisance. If you have any friends owning an iMac, it wouldn’t be a bad idea to let them know of this symptom. It would be also be very nice if you let us know about what the Apple technicians said to you. Wish you best of luck…

    Mark Barnes
    5/16/11 @ 2:15 pm


    I live in the UK and have the same problem. I bought my first iMac27″ last August and noticed the dark stains a few months back. I took the machine back to the store (not an easy job due to the size and weight of the thing!) and they kept it at the store for two weeks whilst trying to fix it. Eventually they gave me a new machine. This lasted 6 weeks before the screen stains returned. Back to the Apple store once again – and this time they installed a new screen. The new screen was awful, a horrid yellow tinge towards the bottom. So once again, I took it back to the store. They gave me my 3rd iMac in 9 months.

    I am fully expecting the problem to return. Whilst in the Apple store I met a nice old couple who were bringing their machine back for the same reason and a young guy too. My brothers iMac has now been affected too. Coincidence???

    Something is terribly wrong with the design.

      5/19/11 @ 4:32 pm

      Hi Mark

      It seems that the “stain” problem also affects the larger iMac model. I can actually imagine your frustration after paying the third visit to the Apple store! Well, what can I say… At least the guys over there did twice the best they could and replaced the whole computer. Unfortunately, by doing this they just offered you (and us of course) a strong argument supporting the “defective design” or “defective batch” theory. It looks like the whole thing spreads like an infectious disease to iMacs around your community.
      By the way, did the technicians mention anything about being aware of this specific problem and intending to report it to Apple? Or did they act like never having seen the stains before?
      I wish best of luck for you & your (third) iMac. It would be nice to hear from you any further news about this nuisance…
      Best regards

    5/22/11 @ 5:42 pm

    Meh… I’m on my third screen now, and it’s starting to happen again… I think it’s an issue with heat. Whatever it is, it has been plaguing iMacs since 2008, from what I can gather, and Apple really needs to own up to it and sort out the problem.

      5/29/11 @ 1:33 pm

      “Heat” or “no heat”, the problem exists for many users around the world and Apple, as long as I know, doesn’t seem to accept its responsibilities! Why? Perhaps because we are talking about massive product recalls… Not so righteous behavior from a respected brand name! I wonder what’s Gary’s opinion after all these comments posted here on this topic…
      Thanks again for allowing me as a guest to your forum.

        5/29/11 @ 1:39 pm

        Don’t really have an opinion on this. Opinions are my main thing. Tutorials are. If you have an iMac with a problem, I’d take it back like you would with any other problem. I’m a Mac Pro and MacBook Pro user, I don’t have one of the current iMacs so I haven’t experienced the problem myself. But I have to think the numbers still show this is a problem for a small number of users. Enough that people find each other in forums like this one, but clearly still a small minority.

    8/7/11 @ 8:49 am

    I am having the same problem. I sent my iMac back last Friday for repair and I was really lucky to notice the stains right when they started appearing because I had mere 10 days left of warranty. I really didn’t want to buy the Apple extended warranty, I sincerely thought that I would never have a problem with my iMac,”When you buy a computer, you want it to last. And a Mac will.”, but, as I still can, I will now, I can’t imagine having this problem again in another year and not being covered by the warranty… I really wouldn’t have the money to pay for it, buying it was a big sacrifice.
    Could you figure anything else about this matter Jim?
    Anyone with ideas on how to prevent this problem?


    5/7/12 @ 8:56 am

    Same problem here. I paid $3000.00 for my iMac and it turned out that after six months using a stain in the right corner came. I thought that its not clean so I tried to wipe the monitor but sill it is on. So I googled the problem and found out that iMacs are not perfect as they look. Now I am so pissed off, because I am a former pc user, and my 10 year old HP pc turned out to be more resistant and with better quality.

    10/19/12 @ 8:25 pm

    My iMac is about years old, and I also get black spots. My problem may not be the same, but I think it’s caused by dust, and dirt forming on the outside of the screen. The reason, I think this is because, I can make the spot smaller, and less dark, by lengthy & vigorous scrubbing, wt a screen cleaning cloth. Either it is on the outside, or using the cloth on the screen, moves the dirt about below the screen. The spot also moves some, when scrubbing. Still I have never been completely able to remove the spot, and it grows again over time.

    10/19/12 @ 8:26 pm

    3 years

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