Persistent horizontal lines appear on iMac screen

Same issue with me, a 2021 apple M1. This is my fourth iMac and very first time a quality issue arises. Horizontal lines at the bottom of the screen. Really hope apple comes with a repair plan for this.

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A problem has recently happened to me. The bottom third of my Imac M1 screen became suddenly greyed with horizontal lines, accompanied by disturbing intermittent flashing at the interface between the lined area and the OK area. Clearly a hardware fault (it doesn't appear on screenshots) and no obvious causation as the Imac has not been moved for its position for two years and has suffered no impacts whatsoever at any time. I have an appointment with my local Genius Bar on Friday, and will report the response here and elsewhere.

I am very unhappy. I have been using desktops since 1984 and Apples since my 1994 Colour Classic, and have never encountered a hardware fault. My faith in Apple has already been significantly affected, and if I receive the same response that some others on this thread have received, I will be very unhappy indeed.

I also have this problem, 14 months old. It happened suddenly in the middle of the day.

It's not really useable now. It's a defect with the screen, I used a secondary display, my TV and it looks fine.

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I've just had my iMac M1 have the exact same happen. It hasn't been moved or put under any sort of stress since I first purchased it in December 2021 (max price for max spec) and I am devastated. I cannot afford the repair quote that the Genius Bar will suggest and frankly I don't want to be risking further damage by transporting it to and from the Apple Store. I've been a customer since 2009, this is the first serious issue I've ever experienced with any of my Apple products over the years.

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I had a massive failure on the SSD of my Intel Macbook pro 16 inch after making a regular os update. That's why I don't update my M1 iMac , just left it in OS 14.7, but today the horizontal lines issue has happened to me.

The same thing just happened to my 2021 M1 iMac.

There are consistent gray lines that formed 3 days, at the bottom section of my screen, that make it impossible to read the text behind it. Taking a screenshot reveals its not a softward issue as the screenshots to now show the lines. It's a hardware issue and I'm not sure how to fix it as the comptuer itself is built into the screen. I cannot replace just the screen on an iMac. I'm posting a picture from my phone (since screenshots do not help) - attached

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Wow - screen failed - Apple Care has refused to repair … they gave ‘no responsibilities’ 1200 AUS$ repair …. I have an SE30 from the ‘80’s and multiple desktops since … never had a screen fail like this in 40 years … surely there needs to be acknowledgement of the issue?

Unfortunately my 2021 iMac is suddenly showing the grey horizontal lines too. So this is obviously a defective manufacturing issue that apple is well aware of. Lesson learned and I will not be replacing it with a new Mac or any other apple product for that matter. I was quoted an absurd amount to fix this out of warranty.

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Another "victim" of this problem here 👋🏻 Recently brought in my iMac M1 24" (four ports) to the Apple Orchard Store in Singapore to get it checked by the technician who confirmed a "display issue" requiring fixing by display replacement. Unfortunately for me this issue surfaced just three months after my AppleCare+ extended warranty lapsed earlier this year🫨, and I'd initially ignored it/lived with it as it didn't really affect my daily usage back then (with just a few horizontal black lines at the bottom of the screen).

Photos attached are taken recently when the black lines suddenly multiplied for no good reason and now appear right smack in the middle of the screen, obviously hindering proper usage and hence I contacted Apple Support to seek help for a waiver of the hefty repair costs quoted (approx SGD$1K)- especially as this seems to clearly be a manufacturing issue and not the user's fault?! i.e. no physical damage or mishandling of device; in fact my iMac has been well taken care of (and cherished lol)🥹 I mean, just by taking a look at this thread and a few others both on Apple forum and other external forums- the increasing (and considerable) number of user complaints and shared accounts of this issue over the recent couple years since the iMac M1's release in 2021.

Would very much like for Apple to address this issue with the iMac formally, to address grievances of users (and Apple fans sigh) worldwide PLUS offer a recovery program/solution please, without us having to bear additional repair costs unfairly.

Thank you🙏🏻.

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have the same issue appear today. Suddenly a lot of black horizontal in the bottom of my iMac M1 2021 blue 24 inch. I don't know what happens cause working on this Mac, opening some file and go to screen saver when back, this is already there.

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. 

Hello Community,

Sorry for my bad English.

Since 2 Days I have these lines on the display too.

I chatted with Support and his answer was curious : I have to clean my screen. it is dust or something... REALLY ???

I have abt. 10 lines in black and regular 10 lines in white wich disappear every one second, then they come again.

iMAC 2021, M1, 16GB, 2TB SSD

Yours,

Wolle

Mine started showing these multicolour lines in less than a year after purchasing it in July 2022. Sales people didn’t advise of any manufacturer service cover or anything like that. When I went to iStore they wanted to charge me over R36k to repair it - which was ridiculous to say the least. There is no way all users could be having the same issue and Apple doesn’t want to take accountability for this defects, after we spent so much money to purchase these devices. I need a personal laptop desperately, I don’t have money they need to fix it and I can’t just give it away because when I tried to trade it, they offered a fraction of what I spent to buy it - which is unacceptable. Can anyone advise what the best way is to resolve this, please?

Absolutely ! In the years I owned 2 iMacs plus 2 mini and 2 MacBooks but now I say I'll never purchase an iMac again ! Yes It may happen such kind of fault (even if I never happened to me in the past) but the worst thing in my opinion is feeling abandoned. When my iMac 24" M1 showed the fault I had to purchase a new mini (November 2024) and a new monitor (I had some work in progress) for a problem I didn't cause.

Mine has started doing it today as well! Also 24" iMac purchased July 2021, so have had it around 4 years. My previous 2 iMacs lasted around 7 years each and were still working, only replaced them due to needing something speedier.

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