Another case of background apps with vertical lines often showing through on iMac screen (late 2013)

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Another case of background apps with vertical lines often showing through on iMac screen (late 2013)

iMac (27-inch, Late 2013)

3.2 GHz Intel Core i7

16 GB 1600 MHz DDR3

NVIDIA GeForce GTX 780M 4 GB

Running Mojave 10.14.6

I'm having the same issue that documental logs in these two threads:

Background showing through some apps on i… - Apple Community (posted Feb 2019)
Vertical lines, background apps often sho… - Apple Community (posted Nov 2019)

The symptoms of it are identical: an off-and-on appearance of subtle but distracting background icons and app images with thin vertical lines showing through foreground apps on my screen. Screencaps don't show it, but taking a photo of it does.

It's not traditional burn-in because a) it's off and on / intermittent, and b) it's happening with icons that have been in their current location for less than 12 hours. Like documental, I use a screensaver, and my background changes ever 15 minutes - and again, the icons in this image have only been here as of last night.

At times I have seen:

my Chrome bookmark bar faintly through my Discord window when the Chrome window wasn't on screen (but only recently hidden)
my desktop icons or window faintly through my Chrome tabs, and and sometimes window borders
my Chrome window user interface faintly on the background of my iMac
on my even older second monitor, the background faintly through a flat gray image

Suggestions others have made that so far haven't had an impact:

Rebooting (to clear video memory): May cause the problem to disappear, or may not; issue also disappears at random, as far as I can tell
Turning on Reduce Transparency in System Preferences => Accessibility => Display
Moving icons from their previous locations generally still shows the new placement, if the issue is happening at the time
Resetting the NVRAM, assuming I held down the proper keys for the proper amount of time (pretty sure I did)

I'm hoping this isn't the GPU dying as they suggested. (OP, if you see this, did you ever fix the problem?)

iMac 27″

Posted on Apr 4, 2025 3:52 PM

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Answer 1

den.thed

Level 10

85,090 points

Apr 4, 2025 4:14 PM in response to spiritchrysalis

Have a look at > Avoiding image persistence on Apple LCD displays - Apple Support (DE)

Leaving Icons up in the same place for any length of time will cause that issue.

What I recommend is:

1) turn on Reduce Transparency.

2) set the display to Turn Off after 10 or 15 minutes.

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Answer 2

Apr 4, 2025 4:59 PM in response to den.thed

Hi,

Thanks for your reply, den.thed, but those things were either already true (setting the display to turn off), or were already tried per my original post (reducing transparency). This isn't image persistence.

They were also tried by the other person who posted a thread about this back in February 2019 [I believe this is the direct link - Background showing through some apps on i… - Apple Community], but I'll quote him here:

"Thanks, but that's not my issue. It's not 'image persistance' it happens in real time with what is behind the window. For example if I move the Chrome window in the background, it shows through Premiere in the new position immediately. Screen saver timings etc. are not a solution here unfortunately."

Does that help clarify? If so, any other suggestions?

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Another case of background apps with vertical lines often showing through on iMac screen (late 2013)