Weird 'hazy' grey border on iMac screen

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Level 1

10 points

Weird 'hazy' grey border on iMac screen

Hello,

I've got a really weird issue with my iMac (late 2013) screen.

Basically, a few weeks ago it started showing this really strange whitish screen border anytime I woke up the computer. Please see attached pictures.

I obviously panicked at first, and thought the screen was broken, but with big surprise the border started to slowly fade out as I was using the computer. Let's say in around 20/30 minutes the haze was gone.

It definitely looks like there's some moisture between the screen and the protective glass - which makes sense, as it disappears as soon as the computer heats up - but as far as I know on these models the glass is laminated, so not sure how moisture can get in between.

Also, very IMPORTANT: this does NOT happen when I shut the computer down. It just happens when I put the computer at sleep.

Not sure what this means.

Any ideas?

Thank you

L

ps: I've run the hardware test already - all good

iMac Line (2012 and Later)

Posted on Feb 6, 2019 7:54 AM

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Answer 1

Best reply

rkaufmann87

Level 10

141,348 points

Feb 6, 2019 8:01 AM in response to luca4cmp

It would be wise to take it to your local Apple Store or AASP to be professionally diagnosed. You may be correct about moisture or it could be a failing GPU or display. Anything we would suggest would be a guess, therefore my suggestion to take it in to someone that has the proper tools to diagnose it.

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Answer 2

ProbsRus

Level 4

1,126 points

Feb 6, 2019 9:19 AM in response to luca4cmp

I've been working on computers a long time, and I have never seen anything quite like that. If it were condensation then you normally wouldn't expect to see it light up like is shown in the last image. It also wouldn't normally be so uniform. I would normally suspect some piece of unknown software or a desktop pattern effect designed specifically for the holidays to make it look like a frosted or snowy window because it looks so perfect. The only part that challenges this theory is that the issue also shows up in the diagnostic screen.

I agree with rkaufmann87 that you may need to take it in for evaluation, but before doing so I think it's worth trying a few things to rule out software.

1) Create a new user and try using it to see if the same issue occurs.

How to test an issue in another user account on your Mac - Apple Support

2) Reset SMC and NVRAM. I don't think this will have any effect, but it can't hurt either. Since this is a mystery issue it's worth trying as many simple things as possible before taking it in.

Reset NVRAM or PRAM on your Mac - Apple Support

How to reset the System Management Controller (SMC) on your Mac - Apple Support

3) Does the same issue occur in safe mode?

Use safe mode to isolate issues with your Mac - Apple Support

The reason I feel comfortable ruling out condensation is that in the images you posted I can see alternating columns of pixels that are brighter than expected. Condensation would affect the entire region and not discriminate between columns of pixels as shown below in a closeup taken from your image. Also, the formation of condensation, if even possible on this type of display, would be dependent on your environmental conditions. If your computer was located in a warm humid environment and you suddenly pull nice cool air-conditioned air through the computer then that could contribute to the formation of condensation. Warm air holds a lot more moisture than cold air, so when the air is cooled the moisture in the air condenses out onto the cooler surfaces. Here's a post from long ago showing an example of what condensation looked like on an iMac with the removable glass panel.

https://forums.macrumors.com/threads/white-steam-smoke-behind-imac-glass.873292/

I am very curious about how you ultimately resolve this issue. I just wish I could provide more suggestions. You can help us all be sharing the solution so we can pass it on to others if we ever see somebody post something similar in the future. Good luck.

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Answer 3

luca4cmp Author

Level 1

10 points

Feb 7, 2019 2:06 AM in response to ProbsRus

e.g. this is a picture showing the effect on the screen after just 5 minutes of computer into sleep mode.

It'll go away completely in about 10 minutes...

Again, if I shut the computer down, this does NOT happen....so weird!

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Answer 4

luca4cmp Author

Level 1

10 points

Feb 7, 2019 2:05 AM in response to ProbsRus

hey guys,

thank you for your kind answer.

It is definitely not a software issue, for the simple reason that, once the screen goes into that 'hazy state', then it stays like that until it heats back up, no matter if I'm logged in or logged out. Basically, even if I restart the computer, the white border is there from the very first second the screen gets the backlight (i.e. when I see the apple).

That means it has nothing to do with the OS.

Also, I wouldn't suspect a faulty GPU, otherwise how could this gradually fade out in like 20 minutes? It is definitely the screen warming up.

I'll do an NVRAM reset later today, although I'm quite sure it won't do much.

My biggest fear is that those pixels have been actually damaged from a prolonged usage, mostly because (I know it's a wrong habit) I rarely shut the computer down...for 4 years I've been pretty much just put the computer to sleep...

My question is: what does actually happen to the screen when the computer goes into sleep mode?

Does it still get something from the GPU? Does it still get a minimum current? (very ignorant about screens, sorry...)

My knowledge about this was that the screen in sleep mode is totally off, but I don't know really...

It is a big heavy computer and before taking it to an apple centre, I'd like to see if someone else in the world has ever seen this before...

Thanks again

L

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Weird 'hazy' grey border on iMac screen

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