Persistent horizontal lines appear on iMac screen

Hi everyone. Please be sure to report this issue directly to Apple via the Support Chat at https://getsupport.apple.com/solutions. They now have an Apple internal tracking number to capture reports specifically for this display issue on the 2021 iMac. If all goes well, this is a pre-cursor to an official out of warranty free repair program.

I learned about this while at the Genius bar with my 2021 iMac. The tech showed me the info on his support device that this issue is being tracked under an official Apple support issue number. It was like EF something. Anyway, DEFINITELY REPORT THIS ISSUE DIRECTLY TO APPLE SUPPORT!

Hi everyone. As promised, here's my story of getting a replacement iMac without paying money but effort and time. I'll only present below the timeline of my story and a few comments for brevity (since what I have done is as same as what have been told in this thread):

• June 2021: bought iMac M1 in Spain. I didn't purchase AppleCare because Spanish law provides 2 year warranty (later even extended to 3 year warranty). Since iMac always stands at one place, meaning little risk of accidental damage, double insurances for 2/3 years (AppleCare + warranty provided by law) seem excessive
• May 2024: flickering horizontal lines suddenly appeared in the screen (totally out of blue)
• Soon visited Apple Genius Bar to ask about solution without bringing in my iMac, and was told the screen needed to be replaced on my cost
• September 2024: visited again Apple Genius Bar and brought my iMac with me. The staff examined my iMac and suggested the same solution as before
• October 2024: contacted Apple via chat, and was given a phone call, where talked to a lady first, and then a senior advisor. As result, no change to the solution offered
• Afterwards wrote a formal feedback to Apple about my iMac
• End of October 2024: suddenly received a phone call from Apple, asking to have a session in order to collect some information about my iMac. System metrics were collected during the session. I was told Apple would analyze the information and decided what to do.
• 2 weeks later, Apple called me and told me that they would like to collect my iMac and provide me a replacement with no cost. The model of the new iMac would be as close as the old one. However, they can not be identical in my case: M1 is not available any more, M4 instead; the basic keyboard of the new model does not have touchID; the basic adapter does not have ethernet interface
• January 2025: I received the new iMac today. It's as expected

Thanks to everyone who contributed to this thread! You guided me step by step in this journey. Wish all of you get a replacement!

I planed buying a few Apple products but halted my plan due to the shock caused by the iMac deficiency. I'm happy I can buy Apple again after the replacement!

Some details: I've started experiencing this issue since yesterday. Fortunately for me, right now it's just one horizontal, 1-pixel-thick black line near the bottom of my screen, which sometimes turns into multiple flickering lines (this happens when the brightness goes up, I think. I have turned off the auto-brightness and am using my iMac at low brightness as I'm not willing to test this hypothesis). I bought my M1 iMac in June of 2021, immediately after it was released here in India. It's a lightly used machine without a single scratch.

As I mentioned earlier, I kind of know what led up to this issue in my case. I recently updated my iMac to Sequoia 15.0.1. I usually never update to a new OS this early. Then, the night before the display issue, I was checking out the animated/dynamic screen-savers/wallpapers from Apple (I haven't checked them out before, so I was curious). A few minutes later my machine hung up and I had to force shut down by long-pressing the power button. I didn't think much about it and went to sleep. The next day, as I booted my iMac, I started seeing the line.

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I spent a couple of days talking to Apple support and taking my Mac to an Apple store. The Apple support person said that he could not help me with this as my device was out of warranty (I did mention about this thread to him). I did not get an answer on how to stop this issue from getting worse. The price quoted to me to replace the screen is Rs.60000, or about $700 USD.

Is the consensus here that the iMac display will progressively worsen as I keep using it? I can live with a few lines at the bottom of my display. Right now it is not too distracting to me. But from what I've read the lines grow with time.

You’re not entitled to any refunds for post-warranty service, unfortunately. Furthermore, unverifiable opinions/assurances volunteered verbally at the time were good faith, friendly advice based on the inspection then, not official recommendations on how to proceed or provide guarantees that the machine would not deteriorate further.

Apple will be in touch with you if their position changes, which is unlikely since the issues did not crop up during the warranty period. Not to mention subsequent deterioration of your machine to a “fire hazard” condition which suggests an operating environment unique to yours.

My advice to you would be to discontinue using your Mac and storing it away in the remote chance that Apple contacts you. Then buy new, Apple or non-Apple whatever suits you best

Bottom line: It is what it is and if it isn’t any longer, Apple will contact you directly. Ranting on this forum with unverifiable one-sided narratives achieves absolutely nothing. All the best!

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.

One of these two iMacs cannot be turned on today. Not sure if this is due to the worsening of the short circuit. Yesterday, I connected to an external monitor and it worked fine. Turn off the iMac overnight, then it is no longer turning on starting this morning. So frustrating.

Thank you for sharing some good news, although I would not "sincerely thank" Apple until it is under the official Service Program. If the design and material is being the same, it is likely going to happen again in the next +24 months.

UPDATE: I got Apple covered the display hardware fee

Here are my suggestions to whom having the same issue.

1. Make a Genius Bar appointment for further examination. Genius Bar will mark a note if there were any visible abuse/damage to the product. Note: Authorized service providers can also examine your iMac but will incur a fee even you decide not to repair.
2. Share with the Genius the evidence you have. Ask for a free repair politely as the issue is so widespread. However, don’t expect any positive result from here. This is only for recording purpose.
3. Reject the expensive repair cost quotation, and bring the iMac back.
4. Get online support. Give the 1st level advisor the related links, including this thread, to show this is a widespread issue.
5. Ask the 1st level advisor to escalate to a Senior Adviser. The senior adviser will call you by phone. Ask him/her to read the links you sent earlier first.
6. Insist a formal written reply explaining why this issue is so widespread, or Apple think this is just independent cases. You will get a case ID for this.
7. Use the same case ID, repeat step 5 to 7, in a week or two.

Don't forget to send product feedback from Apple's website, so hopefully it grant an official Service Program one day.

Good luck.

Hey guys,

I posted here a few months ago about my problem, same way as yours, on an iMac M1. Started in august, in December the situation worsened, and in February, beyond the lines, the screen started to get VERY hot. During this time, I contacted Apple several times to report what was happening, even though they refused to repair it. I took photos and videos and documented everything, talked about this discussion and other reports. The situation only changed when I reported that the screen was getting very hot and was passed to a senior support and after a few days took the display for evaluation. It took about six months, many contacts, persistence and patience, two in-person evaluations, and luck to be served by attentive people. But it worked out: in March, I was informed that they granted me an exception (they emphasized this point) and approved the replacement of the display free of charge. I don't know if it was luck, the way things work in Brazil and customer service, or some genuine concern for customers, but it worked out. Keep reporting. I don't know if the feedback really works, but maybe talking to people will. Good luck!

Hello everyone,

I’m adding my voice to the growing number of iMac M1 owners experiencing persistent horizontal lines across the display.

• My iMac is the 24-inch M1 (2021).
• The lines appeared suddenly and are worsening over time.
• When I connect to an external monitor, the issue does not appear, which suggests it’s a built-in display hardware fault and not a GPU/software issue.
• The lines do not appear when taking a screenshot, which suggest according to the apple advisor on the chat that it is a hardware and not a software issue
• I’ve seen many others here and on Reddit/MacRumors describing the exact same problem, often 1.5–2 years after purchase.

This seems to be a widespread defect, not accidental damage. It would be great if Apple could officially acknowledge this and provide support—whether through a repair program or extended coverage.

Has anyone here successfully escalated this with Apple Support and received a repair (in or out of warranty)? If so, could you share how you approached it?

Thanks for any advice, and I hope Apple is listening to the many of us dealing with the same display failure.

I found this on the Apple Support page that shows country of origin by part number. I suppose it can apply to iMacs also.

Origin country of macbook - Apple Community

See Connect an external display to your iMac - Apple Support

We are just users, you need to go to your local Apple support, or send feedback:

Product Feedback - Apple