Persistent horizontal lines appear on iMac screen

Hi, Roi here, from Spain.

I own an iMac 24” M1 (2021), Yellow, 16GB RAM, 1TB SSD, purchased on October 14th, 2021.

A few months ago my display began to show a very specific distortion pattern that keeps getting worse over time:

• There is one permanent dark horizontal line across the middle of the screen.
• From that line downwards, the next ~6 cm look normal.
• Below that, there is an oscillating band of about 1 cm where the horizontal lines grow and shrink continuously (flickering, moiré-like effect).
• And from that point to the bottom edge, the display shows constant horizontal dark lines, completely stable but clearly defective.

A few important details:

• If I take a screenshot, the lines do NOT appear → so the GPU is fine.
• If I connect a second external monitor, that monitor works perfectly → confirming the issue is ONLY on the built-in display panel.
• Restarting, updating macOS, adjusting brightness, or resetting settings does nothing.
• The machine has never been dropped, opened, damaged or mistreated in any way.

So the GPU / M1 chip is fine — this is clearly a panel-level hardware failure.

I’ve never dropped or damaged the iMac; it has been sitting on a desk since day one.

After searching online, I found dozens of reports from other users with the exact same pattern on the 2021 iMac M1, and all of them point to a progressive display panel failure (COF/bonding or internal display driver issues).

The thread “Persistent horizontal lines appear on iMac screen” matches my case almost identically.

I’m posting here to:

1. Add my case to the growing list of affected iMac 24” M1 units.
2. Share this specific pattern in case it helps Apple identify the root cause.
3. Ask whether other users have recently managed to obtain out-of-warranty support or a repair exception.
4. Request guidance from Apple Support or Senior Advisors reading this thread.

I can provide photos, videos and full system details if helpful.

Thanks in advance,

Roi

What happens if you Factory Reset the iMac? Of course after you have Time Machine Backup or backup of some sorts. Erase the whole thing and reinstall Mac OS Clean. Does it show up? Perhaps Reinstall with Ventura that came with it?

Please, everyone:

1. Show the photos of the problem;
2. Which model do you have: 2 or 4 ports?
3. Publish your model number suffixes. It may help to scope out the problematic models;
4. Report it to Apple here https://www.apple.com/feedback/imac/. I'm afraid it's the only way to let Apple know about this problem and motivate them to start an investigation.

Got into a chat with Apple Customer Support. I guess it would help if all of us here will do a chat to Apple and provide this discussion link to them --> Persistent horizontal lines appear on iMa… - Apple Community

Letting Apple know will give traction on this issue. It is really absurd for Apple to charge us big amount of money to fix this hardware issue.

See the screenshot of my chat, and notice the horizontal lines below the screen.

Got into a chat with Apple Customer Support. I guess it would help if all of us here will do a chat to Apple and provide this discussion link to them --> Persistent horizontal lines appear on iMa… - Apple Community

Letting Apple know will give traction on this issue. It is really absurd for Apple to charge us big amount of money to fix this hardware issue.

See the picture of my display with the chat and notice the horizontal lines below the screen.

If the problem is listed here on the link below yes. If not, it is out of warranty by now and you will pay the cost for repair. Unless you have AppleCare coverage then its covered.

Apple Service Programs - Apple Support

The tech that did your analysis was thorough. Thats awesome since it's something Apple Stores people will never do for us. If the part is replaced with the same type of components then failure is again inevitable within 2-3 years. Perhaps if the display is set to 50%-60% and turn off auto brightness to prevent ramping it up higher will help make it last longer? Maybe? Sadly unlike cars which can endanger the passengers life, Federal Agencies monitor this, computers are not subject to same Federal Consumer Safety guidelines for component failure. If that component does not pose a safety risk. Like Fire, explosion type results from a component failure.

Hey everyone! I have a great news.

Thanks to all of you and the thread creator for the evidence, and thanks to Apple for the integrity and standing behind their products.

I was able to get authorization for my case for repair as they are willing to honor it for repair beyond the warranty.

I am now able to go to the store and have it fixed without cost. Will confirm once it's done but I got verified by customer service that I can take it in.

.

From what I've been told, the problem isn't with this cable (which connects between the iMac main PCB and the LCD PCB and would be easily replaced) but with the cable that connects the LCD PCB to the LCD itself.

And to access this cable you have to peel back the LCD glass, which is difficult and easy to damage or break.

That's why Apple's solution is to replace the entire LCD...

Hi everyone,

I’m also experiencing black horizontal lines on my iMac M1’s display. This issue affects my work and overall user experience.

If you’re experiencing black horizontal lines or other display issues on your iMac M1, I encourage you to send feedback directly to Apple. Sharing your experiences can help bring attention to this issue and may lead to a solution.

You can submit your feedback here: Feedback - iMac - Apple

It’s important for us as a community to let Apple know about recurring problems so they can address them effectively.

I've cross-posted this in r/apple on Reddit. Please upvote there as well:

https://www.reddit.com/r/apple/comments/1gzlr7a/apple_please_acknowledge_design_flaw_in_imac_24/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button

Guys, as an update I was able to get Apple Support to grant me a free display replacement. I posted a full update on the interaction here: tiny.cc/5spyzz. It may be a strategy you can try on your own.

I had the same problem. There’s a burn mark on the rim of my screen.

My screen blacked out after 3 weeks and I’ve already turned the brightness to minimum.

I will suggest you to use a dual screen with the second screen set to mirror the first screen now.

Sent feedback to Apple and talked to Apple Support a couple of times but the only answer I got was full price repair or live with the problem. So frustrating.