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 ** 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.


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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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 ** 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!

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Mar 24, 2025 3:44 PM in response to Michael Reid

What you're experiencing is a display problem with early M1 iMacs.


The following topics illustrate the Silicon M1 iMac Display problem:


Screen Failure on 24-inch-iMac, M1, 2021 - Apple Community

Persistent horizontal lines appear on iMac Screen - Apple Community

Horizontal Lines on Screen of iMac, 24", 2021

Horizontal black lines covering bottom 3rd of 2021 M1 iMac screen

Grey horizontal patches on my M1 iMac 2021 model

Horizontal lines at the bottom of iMac(M1,2021) screen

Horizontal Lines on 2001 M1 iMac Display

Persistent horizontal lines and other issues on iMac M1 display


As you've already been urged to do is take it into the nearest Apple Genius Bar for a free diagnostic test. You'll be told that the repair will cost about $600 US and that there is no replacement program currently for the problem. If you take it in you're telling Apple that there are more M1 iMacs with the problem and you'll be in their database if and when there is a repair program initiated.


Some users have opted to get an inexpensive 3rd party monitor and run it with the iMac. It's certainly less expensive than the repair costs.


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Jun 29, 2025 2:52 AM in response to Wendy887

I purchased four M1 iMac 24" in late 2021 for my office, two with lowest specifications, the other two with highest specifications. Unfortunately both of the higher spec iMacs have exactly the same issue started from March and June this year. This is a 50% fail rate after three years of careful use.


It is disappointing as the issue was firstly reported as early as 2023, then hundreds of users expressing "me too" in Apple's forum, Apple seems do not care. I ** sure there are many more customers who experienced the same issue but did not hit the "me too" button.


I talked to online support about my findings, also took the iMacs to Genius Bar despite hours of traveling. While I was 99.9% sure it is a hardware issue, I still followed their advices and wasted hours of playing with the software/hardware issue isolating game, by erasing all content and reinstall Mac OS. The specialists sound empathic, but the options provided are still 1) pay to repair or 2) not to repair. I don't blame them, as they are just following the company's guidelines.


I have sent a feedback to Feedback - iMac - Apple to request for a Service Program. Hopefully Apple takes this issue seriously soon enough so they don't turn loyal promoters into detractors.


If your 2021 iMac 24" is having the same issue, please also send a feedback to Apple, and post your case here. It seems the older thread is closed where I cannot post new comments.


iMac 1:


iMac 2:

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Sep 14, 2024 9:32 PM in response to Wendy887

You are not speaking to Apple on these forums, they are the hosts however they DO NOT read or participate in user to user forums.


If you want your voice to be heard please post at www.apple.com/feedback. They will not answer you directly however your post will be read.

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Oct 21, 2024 7:52 AM in response to Wendy887

Submit feedback to Apple at www.apple.com/feedback and then make an appointment at your local Apple Authorized Service Provider have it serviced and repaired. Apple has not announced any repair programs for what you are experiencing, if/when they do your out-of-pocket expense will be reimbursed.



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Oct 20, 2024 8:35 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
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Apr 16, 2025 5:39 AM in response to Wendy887

Hi,

Same here, *** mine in October 2021 and the problem started a few months ago.

It's very annoying and gives you seizures/headaches because of the "strobe"effect.

Tried everything (reinstalling macOS, updating, leaving of off for days) and nothing worked.

Hope Apple recognize the problem and extend to its repair program.

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May 7, 2025 8:07 AM in response to Wendy887

Just *** the same issue today. The horizontal lines are flickering near the bottom of the screen. It is not much of a bother for now, but I'm worried that the issue will become worse soon.


I bought my iMac in 2022, thus the issue popped up after 3 years of frequent daily use. It is a bit longer than others. I'm not using Auto Brightness, and the Brightness level is relatively low all the time.



Just posted as we are on the same boat 🤞, and looking for a feasible solution from Apple.




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Jun 4, 2025 2:25 PM in response to MemerGamer

MemerGamer wrote:

That’s planned obsolescence for you. My 2006 MacBook Pro (I know it’s not an iMac) works fine including the screen (I think it has a CCFL backlight) but this happens with about everything these days sadly. I’ve *** a microwave that’s under a 1 year warranty that’s losing power and before that one we had a sharp microwave from the early 90s

It's not planned obsolescence. It's a manufacturing defect that only affect a small subset of M1 iMacs.


As for your microwave oven, maybe you're just like Joe Bfstplk, always under a cloud, bad luck just follows you. Get it fixed under warranty.



Remember what Forrest Gump says: "It happens".



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Horizontal Lines on Screen of iMac, 24", 2021

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