Persistent horizontal lines appear on iMac screen

Dear Old Toad,

According to Apple support, it's an LCD malfunction and the only solution is to replace it.

So it's not a software problem.

It's a hardware problem.

That's already established.

So to everyone who has this problem, there's no point in wasting time trying to find out which App is causing it or which OS update is to blame and reinstalling the OS and all the Apps again and risking losing data trying to solve a problem that has already been determined to be a hardware issue.

I have discovered that if you keep the display at half, the black lines remain at a barely there level and the screen remains cool to the touch. I think it is using the display at full that causes the problem. It is burning too bright and the machine is not equipped to handle it and then the screen burns itself out.

Mine had this problem too first like this:

i'm using it only for browsing and watch youtube, it not dissappear after I upgrade to sonoma, If I touch on the corner left upper on my display screen it overheat like it will burn my finger:

I bought this iMac on Yogyakarta Indonesia on November 2021 and after 2 yers 5 month use, my iMac turn like this. So I decide to bring to AASP (Authorized Apple Service Provider) because on Indonesia doesn't have yet an Apple Store Official. The diagnosed that LCD failure so I have to replace it for around 800$ or 13Million Rupiah. I canceled the offer and bring back my iMac after a week for diagnosed. When I turn it ON again, the flickering were dissappear but the new line appear like this:

it happen globally not only on one or two area, it LCD defect or manufacture failure because many people have same symptoms.

@allrighty

Read My other comment on the first page, I posted a case number, the moderators removed the full number but I think that should be enough to prove your case. I believe any apple supervisor who reads this thread, in their right judgment would agree that the issue is APPLE manufacturing and this is why they were willing to offer it to me to fix it.

So if we all calmly and kindly let them know and get to the top level and make a request, they will make the best choice to protect their own brand for long-term success.

I had the same issue with my iMac 24" M1 2021 after using it for 2.5 years.

After reading all the threads related to this issue, I've contacted Apple chat support and tried to negotiate a free repair for this widespread issue.

Apple chat support said that they don't have the authority to do this and ask me to contact phone support. Phone support said the same thing and asked me to take the iMac and go to Apple store. And Apple Store support said they can't do anything unless the issue appears in this Apple Service Programs list, and he suggested me to leave a message in Apple Feedback.

What happened next was that the rim became super hot when the iMac was switched on even though I've already turned the brightness of the screen to the lowest. There's a burn mark at the rim on the left-hand side and I believe there's a short circuit inside.

The screen blacked out after 3 weeks and it is now completely dead.

Same issue. Bought my M1 iMac 2021 (which I love!) in April 2023 and the line appeared on my screen last week. I contacted Apple and was told to re-install the OS. I did, and the issue was not resolved. I was then told to take it to an Apple authorized repair place, which I did. The diagnostic (which cost me about $65) was clear: no issues with anything, so "as per Apple's troubleshooting flow, the display must be replaced". They would be charging me over $1,100 (in Canadian dollars) for the repair, which is about half the original cost!!! I said no, went back today to pick up my device and am now deciding on the next steps. My computer is only 19 months old. My previous iMac lasted me ELEVEN years! And it's still working, but slower, of course.

I went on the site to provide Feedback, but the box only allows a limited number of characters, so you can't go into details. I wanted to tell them how disappointed I am that a machine so expensive fails in just over a year and a half. I also wanted them to know that I am more than loyal to Apple (numerous devices in my household over the years - from iMac to iPhone, iPod, iPad, HomePod...everything but the watch!), and that my complaint is valid. Now that I see 18 pages of comments from users having the same problem, it makes it even more real. Apple MUST deal with this issue and find a solution!

I also used the chat and a very nice fellow took down my comments (the ones I wanted to put in the Feedback box) and told me he would escalate my issue. I have a case number, so I can follow up in a while, I suppose, but the problem now is that I have to continue using a faulty computer for the time being.

I understand that Apple is aware of this issue.

Based on my personal experience, I would offer the following advice:

Recommendations:

1. Exercise patience—this process may require significant time and persistence.
2. Maintain a professional and polite demeanor when interacting with Apple customer support.
3. Clearly articulate your situation and respond positively and cooperatively to all requests, even if they seem numerous or personal.

Important Considerations:

1. Requests for detailed information or additional steps indicate that the support team is actively working to resolve the issue. A professional, friendly, and cooperative approach on your part will help foster a productive interaction.
2. The individual handling your case has a responsibility to collect comprehensive details to address the matter effectively. This may include intrusive or personal questions and, in some cases, granting limited remote access to your iMac.
3. While some requests may seem inconvenient, they are part of a professional troubleshooting process expected from Apple.

After completing these steps, you may need to wait. If follow-ups are necessary, do so politely and emphasize that the problem appears to be a hardware issue affecting certain units of this model — an issue that should not occur under normal circumstances. Express confidence in a fair resolution and a willingness to collaborate towards a solution.

Finally, based on Apple’s history of addressing similar unexpected issues, I believe it is likely that they will introduce a support program for this specific problem in the coming year. Until then, I recommend maintaining patience, faith, and optimism.

It’s concerning that there hasn’t been an official response from Apple regarding the extent of the black horizontal lines issue on iMac M1 displays. This lack of transparency makes it hard for users to evaluate the risks of keeping their current machines. While some technicians have mentioned this could be related to a specific batch, there is no confirmation or clear information. Without clarification, the possibility of recurrence remains uncertain, leaving users with questions.

In my situation, I explored every possible avenue to address the issue, as this kind of defect does not align with the expected quality and durability that Apple products are known for. Devices like the iMac M1 are generally expected to last for many years, so encountering such a defect within two or three years of use is unexpected.

Given the uncertainty, one good option to consider would be replacing the iMac M1 with a Mac Mini paired with an external monitor. Ideally, Apple could assist users by offering a Mac Mini M1 along with financial support or an equivalent external monitor. A high-quality monitor can often be found for $300 to $400. This setup would reduce the financial risks associated with the integrated design of the iMac M1, where repairs can cost up to $1,200, while allowing users to manage potential future expenses by replacing only the external monitor if needed.

Hi @Universall

It seems you’ve encountered the same issue with floating lines as many of us. However, in your case, there appears to be an additional defect.

The dark spot in the top-right corner of your monitor indicates a separation between the LCD screen and the protective glass. Since these layers are glued together, the separation likely caused the LCD to crack, leaving the affected pixels permanently black.

This could have resulted from one of two possibilities:

1. A deliberate attempt to separate the LCD from the glass—perhaps to access the internal circuitry, such as the side cables.
2. A significant temperature increase that caused the adhesive to weaken, leading to the separation and subsequent damage.

In my opinion, it’s more likely that the damage occurred inadvertently, possibly during a prior inspection. When you asked the technicians to assess the fault, they may have attempted to separate the LCD from the glass, unintentionally causing the breakage.

To address this, I recommend being persistent and extremely polite when dealing with Apple’s support team. Always request to escalate your case to a supervisor, as standard employees may not have the authority to take your complaint to the necessary level.

Patience, thoroughness, friendliness, and good manners will be crucial in resolving this matter. This issue affects not just you but also Apple, whose reputation is at stake due to this widespread failure.

Best of luck!

[Edited by Moderator]

Hi,

I also Have same issue, contacted Apple India about same for 3-4 times over last 7 months but Apple is knowingly accepting that it’s on customer, Apple can provide repair at cost ~₹ 55000-60000 ($800-900 USD).

as per Apple support, They aren’t coming up any service program.

You have 3 options:

1 - have Apple repair the screen at a quoted price. 

2 - add a 3rd party monitor while darkening the iMac's screen.

3 - replace the iMac with a new M4 Mini: a 10 Core Mac Mini M4 with 16 GB RAM and 1 TB SSD ($999 + tax) with a 27" LG 4k monitor ($250 + tax from Amazon.com)  is $1249 + tax which is $560 less than a similarly configured new 24" iMac ($1799 + tax)  re 07/2025.  

I just got the above new Mini M4 with a 32" 4K LG monitor w/speakers (didn't realize the Mini came with a speaker). It was around $550 less than a. comparably configured new iMac.   You can always order more RAM, storage and cores in the CPU if needed. 

This same thing happened to me as well. I also reported it to Apple Support the same way and they gave me the internal tracking reference for this display issue. After that, thankfully my iMac got fixed. So yes, definitely report it through the Apple Support link shared above. https://getsupport.apple.com/products https://choosemaid.com/ Product Feedback - Apple

Just yesterday.. my M3 iMac Suddenly have lines appear at the bottom... This is ... I got 3 iMac. At least they are been use to the max without much problems. The ever first iMac I used is way back early 2000. Change the PSU later few months HDD down. My 2nd iMac just beside my latest M3 iMac ( suddenly have lines after using for 1 years + ) The 2nd iMac still function ok. Screen is pinkish sometimes burn mark if I watch Youtube video for sometime or live stream. That is " consider ok for me " since already used over more than one year. After that the screen at least will back to normal.

BUT I can't accept on my M3 iMac.... Only just use for one year+ haven't reach 2 years even 3 years. Suddenly Lines appear... I have done ALL Checks , restart, shut down etc, what take screen shot, what external monitor whatever is confirm due to " hardware " And I check around entire internet. Even Establish Tech website DO mention M1 users encounter lines problem suddenly. I was kinda shock even those using M1 iMac also encounter yet I having M3 iMac also encounter this problem...

I have speak to Apple advisor, end up as usual tell me bring to apple store check. OBVIOUSLY end up you need to pay get it fix. I mean , as users We Never abuse the iMac , just use as per normal. Base on all the reply here already shown Obviously the design got flaws and we as Apple supporter Have to Suffer due to this ....

I don't know... Currently no choice I still using my M3 iMac. Those lines lucky appear at the bottom at least I try to " force my eyes don't keep looking at the bottom too much ...but end of the day well... " Now My worry is these lines might be spread even further cover the entire screen literally you can't see the iMac screen ...

Side note I from Singapore here. I have check online with fellow M3 iMac locals they also encounter this Lines suddenly appear issue . Bring to SG Apple store, Same reply need to pay get it fix. Some users just use Dell monitor as external monitor since the repair cost is near 1k. Whereas some users just like me continue to use it sadly...despite those lines on the iMac screen.

Sad to say... we are screw . According from one tech go study how the M series iMac design like etc and why more and more M series users complain/feed back suddenly have lines appear on their screen yet they never abuse, knock it . Well take care of it after using for one year or so this Lines suddenly appear....

He mention is due to design flaws come the display to the cable stuffs like that thus can easily get overheated as time go by it will naturally burn out etc this is why so coincidence the timeline which more and more M series users complain lines suddenly appear is roughly after one year or so..

He claim even you replace the screen , this line problem will come back after using the iMac for one year can't confirm it fix due to the Design is like that ....how the display , cables layout etc which unlike the old intel iMac.

Hello,

I have the exact same issue on my iMac 24" M1 (2021) in Germany.

Support sent me to the Apple Store, the Store sent me back to Support — no one took responsibility. Same reply every time: “older device, no warranty, no replacement program.”

I have now sent emails to Tim Cook, Executive Relations, and the responsible departments in Germany.

Here is my detailed post with more information:

iMac 24" M1 (2021) – horizontal lines + S… - Apple Community