Horizontal Lines on Screen of iMac, 24", 2021

A continuation of closed topic: Persistent horizontal lines appear on iMa… - Apple Community


This morning, horizontal lines appeared across the lower 2/3 of the screen on my iMac computer, purchased in August of 2021. It happened the morning after an auto-update to Sonoma 14.6.1, but after reading the "Persistent horizontal lines appear on iMac screen" feed in the Community forum, I saw that it was a common hardware issue with the new silicon iMac computers.


The lines downgrade the font quality, and they flicker making using the computer hard on the eyes. This definitely interferes with my work. I have already posted feedback to Apple on https://apple.com/feedback/imac


My iMac is no longer under warrantee, but with this being a common occurrence with the silicon iMacs, I am hoping that Apple will stand by its products and its good name by either repairing or replacing the computer at no cost to the consumer.



[Edited by Moderator]

iMac 24″, macOS 14.6

Posted on Sep 2, 2024 10:33 AM

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Posted on Sep 2, 2024 10:54 AM

Hi,

This is a common issue on new iMac. I hope Apple would recall program about it.


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71 replies

Mar 3, 2025 10:50 PM in response to Wendy887

Hi everyone,


I'm experiencing persistent screen flickering on my M1 iMac (purchased in September 2022), and I'm not sure how to proceed. The flickering intensity seems directly tied to screen brightness—higher brightness levels render the flickering lines for a longer duration, while at lower brightness, they appear less frequently.


Several reputable news sources have covered this issue, highlighting that it affects multiple M1 iMac users globally. Given that I am in Gwalior, Madhya Pradesh, India, where extreme summer heatwaves are common, I’m concerned about the long-term reliability of my device.


My Current Situation

  • I use this iMac as my primary work computer for freelance work.
  • I recently moved back home from city life and cannot afford immediate repairs or a replacement.
  • I’ve already spent a lot on my convocation travel (Feb 24 – Mar 1, 2025) and late college fees, impacting my savings.
  • I also pay a monthly EMI for my education loan, so additional expenses are difficult.
  • External monitor? I can’t afford one right now.
  • Apple Authorized Service Centers? I don't trust third-party centers in my area based on past experiences.
  • Taking the iMac to Delhi? Not an option due to travel and accommodation costs.
  • My iPad no longer works, so I’ve stopped digital drawing altogether.


Timeline of the Issue

  • The first minor flicker appeared a week before my convocation trip (mid-February 2025), but it disappeared on its own.
  • After I returned home on March 1, 2025, the flickering became persistent and hasn't gone away since.
  • The iMac has never been moved since I unboxed it in September 2022.


Concerns & Next Steps

I bought this iMac considering Apple’s reputation for longevity, but right now, it feels like a gamble. I’m stuck deciding whether to repair it (which might be costly) or invest further into a product with known issues.


Has anyone here faced a similar issue?

What are my possible solutions without breaking the bank?


Would appreciate any guidance.

Thanks!

Oct 20, 2024 08:35 AM in response to Michael Reid

For additional context, I have the following iMac:

iMac (24-inch, M1, 2021)

  • Ports: Two Thunderbolt / USB 4 ports, Two USB 3 ports
  • Chip: 8-core CPU (4 p-cores, 4 e-cores), 8-core GPU
  • Storage: 1TB SSD storage
  • Memory: 16GB unified memory

Ordered on: May 12, 2021


In terms of my exact symptoms, I don't think it's dead pixels. When I run a dead pixel test, I see two distinct issues:

  • Along the bottom rows of pixels, there are three or four alternating black horizontal lines extending across the entire screen, just below the dock
  • In the lower right section of the screen, from the base of the dock up to about 20% to 25% of the display, thicker light grey lines are visible, primarily on the right side. These lines add a textured appearance to the folders in the dock and are especially noticeable on an all-white background

Apr 15, 2025 03:50 AM in response to Wendy887

The same thing happened with my iMac M1 today and also after the device ran out of warranty. The support specialist told me on phone, that i need to pay the repair. When i told him, that there are many other users who have the same problem, he said, this is the first time he's dealing with this issue.


What i've noticed is, that the upper right corner of the display gets incredibly hot. But then after manually cooling it down. The temperature is and stays "low". This is fishy for me.


If the iMac has a production bug which is revealing after some time, in my opinion Apple IS accountable for this bug, even if it appeared after the warranty ended, since how can a customer complain about a hidden bug during warranty when he doesn't even know that the bug exists.


I have an appointment at the genius bar and i hope Apple has the face to offer a fair solution !!!



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Horizontal Lines on Screen of iMac, 24", 2021

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