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iMac 27 inch 2020 - Screen Glitch (Random Lines Appear on Screen)

I've just received my new iMac and noticed that from time to time a line glitch appears on my screen.

It's completely random, I thought it was related to intensive work/heat but sometimes even when the computer is idle I see the line on the screen.


It was really hard to capture it because it's so random, but I manage to record the moment a glitch happens. Unfortunately there's a lot of white background on it which makes it hard to see, but it goes across the entire screen https://www.youtube.com/watch?v=xw8Z4mVgYgE


The iMac is running fine, I ran all sorts of benchmarks for CPU/GPU and it's all OK, but from time to time I see this annoying line on my screen.


iMac Line (2012 and Later)

Posted on Aug 26, 2020 7:21 AM

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Question marked as Top-ranking reply

Posted on Nov 8, 2020 2:27 PM

Try the following: download and apply the macOS Catalina 10.15.7 Combo Update   


It fixes this issue:


• Addresses a graphic issue that may occur on iMac (Retina 5K, 27-inch, 2020) with Radeon Pro 5700 XT


249 replies

iMac 27 inch 2020 - Screen Glitch (Random Lines Appear on Screen)

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