Persistent horizontal lines appear on iMac screen

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

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...