iMac (M1, 2021) Display Issue

[Retroworldnews]

I have this issue with my iMac 2021, Green colour. It is not my main desktop and I use it about twice a week. Typically at 50% screen brightness. Bought in Aug 2021 the black horizontal line issue started intermittently about 3 years, it would cover the lower half of my screen. In Jul 2025, the black horizontal lines suddenly became persistent.

Spoke with Apple on the phone, they are adamant that they could not do anything about it. As long as it does not fall within their policy to do it, the staff could not do anything.

Went to Apple physical service centre, the staff looked at it, without any technical examination and basically rejected any possibility of covering the repair. The only option they could offer is a repair that's S$1089 (Singapore dollars) before taxes.

I usually advocate for Apple's products but this experience is truly terrible.

There's a petition out there, affected users please support:

Sign the Petition

Hold Apple Accountable: Demand Free Repairs for Defective M1 iMac 24-inch Screens

www.change.org

Attaching photos of my screen below:

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Hi , You also from Singapore? Just today my M3 iMac have this lines suddenly appear that the bottom!. I never play game on iMac, only intensive GPU usage just see youtube video and Live stream. Obviously these two tasks is not seriously will affect iMac GPU overheat etc... I never turn off my iMac all along i just put to sleep mode. This morning Still ok as per normal than come night time as usual I wake up the iMac suddenly see those lines at the bottom. I do few restart, even run apple diagnostics. Under Display sadly I see those lines still appear under red, grey , blue colour display.... how you case now? in the end you just use it forget the repair? I do check my warranty is already over.

 

[cheeweewee]

Hi , You also from Singapore? Just today my M3 iMac have this lines suddenly appear that the bottom!. I never play game on iMac, only intensive GPU usage just see youtube video and Live stream. Obviously these two tasks is not seriously will affect iMac GPU overheat etc... I never turn off my iMac all along i just put to sleep mode. This morning Still ok as per normal than come night time as usual I wake up the iMac suddenly see those lines at the bottom. I do few restart, even run apple diagnostics. Under Display sadly I see those lines still appear under red, grey , blue colour display.... how you case now? in the end you just use it forget the repair? I do check my warranty is already over.

Sad to hear that this is still happening to later versions of iMac. What is your purchase date? I supposed if your device is just slightly out of warranty, you might be able to convince Apple to repair for you at no charge.

I spoke to a “Senior” Apple customer service officer. He took a while to search internally on whether he could help me, still not luck. I have submitted this to CASE.

Meanwhile, I purchased a Dell USB-C monitor to continue using the iMac.

 

[Retroworldnews]

Sad to hear that this is still happening to later versions of iMac. What is your purchase date? I supposed if your device is just slightly out of warranty, you might be able to convince Apple to repair for you at no charge.

I spoke to a “Senior” Apple customer service officer. He took a while to search internally on whether he could help me, still not luck. I have submitted this to CASE.

Meanwhile, I purchased a Dell USB-C monitor to continue using the iMac.

is M3 2023 iMac, I already checked warranty is over is not say sightly out. Literally already one year +.You submit to CASE so any updates? I guess also not use end of the day


I do happen live chat with Apple support , End of the day they still want me get the iMac to apple store check , they claim the price " might not be 1k+ so call rumours from fellow Singaporean happen bring their M1 to M3 iMac due to this " Lines problems " " I forget it.... For SURE They will say must Pay to get fix.


Is kinda troublesome for me to bring the iMac too.. I experience before on the old iMac go third party repair fix. That old iMac is really old is my first iMac. Is due to PSU problem later used for few months later HDD break down....

Kinda sad Apple products now a days the Quality is not there... " Is like ONCE it get repair, FOR Sure after few months or so Another new problem surface... "

SO currently how your set up? You using a Dell USB C monitor connect to your M3 iMac? So literally you use short cut keys to make the screen black whereas looking at the Dell monitor using it?


How the connection like? I not say experts on Hardware. So you bought the Dell monitor it come with a USB C cable you connect to which port on your iMac.


Even tech repair iMac do mention this

" Known iMac 24″ (M1 2021) Screen Line Defect: Recently, a flood of user reports has surfaced about horizontal lines permanently appearing on the 24-inch M1 iMac’s display after ~2 years of use. Apple hasn’t officially recalled this, but evidence suggests a hardware design flaw. Technicians discovered that a flex cable in the display carries high voltage (around 50V at full brightness) and tends to overheat and burn out over time, causing short-circuits that produce black horizontal lines. Unfortunately, the only reliable fix for this issue is to replace the entire display assembly, because the cable is bonded to the screen. Apple Support has generally told affected users that an LCD replacement is the solution. However, replacing the screen is costly (often on the order of US $600–$700 for the 24″ iMac), and if the underlying design hasn’t changed, the problem could recur in a couple of years. "

I NEVER use Full brightness. I always set Auto brightness. According from the tech , EVEN you get fix the problem Could Recur in a couple years....

 

[cheeweewee]

is M3 2023 iMac, I already checked warranty is over is not say sightly out. Literally already one year +.You submit to CASE so any updates? I guess also not use end of the day


I do happen live chat with Apple support , End of the day they still want me get the iMac to apple store check , they claim the price " might not be 1k+ so call rumours from fellow Singaporean happen bring their M1 to M3 iMac due to this " Lines problems " " I forget it.... For SURE They will say must Pay to get fix.


Is kinda troublesome for me to bring the iMac too.. I experience before on the old iMac go third party repair fix. That old iMac is really old is my first iMac. Is due to PSU problem later used for few months later HDD break down....

Kinda sad Apple products now a days the Quality is not there... " Is like ONCE it get repair, FOR Sure after few months or so Another new problem surface... "

SO currently how your set up? You using a Dell USB C monitor connect to your M3 iMac? So literally you use short cut keys to make the screen black whereas looking at the Dell monitor using it?


How the connection like? I not say experts on Hardware. So you bought the Dell monitor it come with a USB C cable you connect to which port on your iMac.


Even tech repair iMac do mention this

" Known iMac 24″ (M1 2021) Screen Line Defect: Recently, a flood of user reports has surfaced about horizontal lines permanently appearing on the 24-inch M1 iMac’s display after ~2 years of use. Apple hasn’t officially recalled this, but evidence suggests a hardware design flaw. Technicians discovered that a flex cable in the display carries high voltage (around 50V at full brightness) and tends to overheat and burn out over time, causing short-circuits that produce black horizontal lines. Unfortunately, the only reliable fix for this issue is to replace the entire display assembly, because the cable is bonded to the screen. Apple Support has generally told affected users that an LCD replacement is the solution. However, replacing the screen is costly (often on the order of US $600–$700 for the 24″ iMac), and if the underlying design hasn’t changed, the problem could recur in a couple of years. "

I NEVER use Full brightness. I always set Auto brightness. According from the tech , EVEN you get fix the problem Could Recur in a couple years....

I have not gotten mine fixed yet. Indeed a waste of time to bring to Apple Store, they don’t bother to check and just remind you that it is out of warranty.

I am now using my Dell USB-C monitor and a custom automation to disable the iMac monitor after logging in. And Monitor Control app for adjusting brightness. Not an elegant solution but it works.

Despite the fact that it is not Apple’s legal duty to fix out of warranty devices, I’m still deeply disappointed with how they handled this. And not improving even the later versions of iMac.

 

[Retroworldnews]

I have not gotten mine fixed yet. Indeed a waste of time to bring to Apple Store, they don’t bother to check and just remind you that it is out of warranty.

I am now using my Dell USB-C monitor and a custom automation to disable the iMac monitor after logging in. And Monitor Control app for adjusting brightness. Not an elegant solution but it works.

Despite the fact that it is not Apple’s legal duty to fix out of warranty devices, I’m still deeply disappointed with how they handled this. And not improving even the later versions of iMac.

I noob connect external monitor to iMac , as there are many monitors out there, some don't display quite well.
So you mean the Dell come with USB c cable ? so you just connect to the iMac usb port and do mirror?

for me my work place table cannot put another external monitor as I have another iMac beside this current M3 iMac. The old intel iMac really justify it been used for years than screen got pinkish hue and burn mark but it will gone at least some more already used for years so kinda justify come hardware wear and tear.

But seriously cannot accept this M3 iMac use only just one years suddenly lines appear....

FYI even you managed to get fix , replace the screen. The Line problems will come back after one year. I already mention copy one Tech explaination. He do mention is due to " design flaws thus over time the display cable etc can be overheated easily as time go by " ...

So is kinda useless get repair yet after one year same problem come back...

 

[cheeweewee]

I noob connect external monitor to iMac , as there are many monitors out there, some don't display quite well.
So you mean the Dell come with USB c cable ? so you just connect to the iMac usb port and do mirror?

for me my work place table cannot put another external monitor as I have another iMac beside this current M3 iMac. The old intel iMac really justify it been used for years than screen got pinkish hue and burn mark but it will gone at least some more already used for years so kinda justify come hardware wear and tear.

But seriously cannot accept this M3 iMac use only just one years suddenly lines appear....

FYI even you managed to get fix , replace the screen. The Line problems will come back after one year. I already mention copy one Tech explaination. He do mention is due to " design flaws thus over time the display cable etc can be overheated easily as time go by " ...

So is kinda useless get repair yet after one year same problem come back...

You can look at this monitor:
Dell Pro 24 Plus QHD USB-C Hub Monitor - P2425D

But there are many other USB-C monitors out there. Dell generally has good longevity.

My M1 iMac had the persistent black line issue after 4 years of occasional use, maybe once or twice a week. Hence, it was 3 years over the warranty period. I believe the problem would come back again even if Apple replace the monitor. So you’ll have to operate it at lower brightness and probably put it on an aggressive Display Off schedule.

 

[Retroworldnews]

You can look at this monitor:
Dell Pro 24 Plus QHD USB-C Hub Monitor - P2425D

But there are many other USB-C monitors out there. Dell generally has good longevity.

My M1 iMac had the persistent black line issue after 4 years of occasional use, maybe once or twice a week. Hence, it was 3 years over the warranty period. I believe the problem would come back again even if Apple replace the monitor. So you’ll have to operate it at lower brightness and probably put it on an aggressive Display Off schedule.

Gee you don't even every day using the M1 iMac yet the line issue pop up? For me daily I using my M3 iMac is last weekend suddenly line appear on the bottom... Now i just drag the browser up a bit as below text hard to read due to those lines...

Now my concern is the Lines will spread further one day entire screen... I don't know but I check around it might ..sadly . I have no choice so have to continue use for work. My work station cannot have another external monitor. Even I put this M3 iMac on the floor is quite unconvenient while I sweep/mop the floor.

Yeah the problem will come back even change the screen....

really suck thumb, having the M series iMac yet cannot set to full brightness is really...don't serve the purposes of call enjoy a fine details visual on iMac screen in the first place.....