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:

View attachment 2530213
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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.....

 

[Retroworldnews]

Update , Just curious OP of this thread how it go?

for me , Last year Oct lines suddenly appear at the bottom. Weird is I never do anything around Nov last year the lines disappear one day while i wake up the M3 iMac as usual in the morning. Dec perfect no lines ever appear. My working routine is simple never change. Nothing intensive.

Just this year Jan, Lines suddenly back. It seem the lines increase a lot. All still at the bottom. I still using it as I don't have space to place external monitor in fact I don't even own one.

So I go search around , some claim do this?

Disable True Tone & Auto Brightness? And Disable automatic grahpic switching? It do help to stop screen flicker and line issue?

 

[cheeweewee]

Update , Just curious OP of this thread how it go?

for me , Last year Oct lines suddenly appear at the bottom. Weird is I never do anything around Nov last year the lines disappear one day while i wake up the M3 iMac as usual in the morning. Dec perfect no lines ever appear. My working routine is simple never change. Nothing intensive.

Just this year Jan, Lines suddenly back. It seem the lines increase a lot. All still at the bottom. I still using it as I don't have space to place external monitor in fact I don't even own one.

So I go search around , some claim do this?

Disable True Tone & Auto Brightness? And Disable automatic grahpic switching? It do help to stop screen flicker and line issue?

I’m inclined to think that it’s a hardware issue, I don’t think those setting would make any difference. Apple does not budge and would not do a repair for my M1 iMac, but since your unit is newer, you should contact their customer service as soon as possible to see if something can be worked out. Otherwise, the next best option is to get a second monitor and use a script to disable the built in monitor. That’s how I am using it now.

 

[Retroworldnews]

I’m inclined to think that it’s a hardware issue, I don’t think those setting would make any difference. Apple does not budge and would not do a repair for my M1 iMac, but since your unit is newer, you should contact their customer service as soon as possible to see if something can be worked out. Otherwise, the next best option is to get a second monitor and use a script to disable the built in monitor. That’s how I am using it now.

how your set up now look like? What script ? I not say technical good. Well I do call , as Expected the senior tech support side claim I have to pay for screen replacement. I already expected that as from the Apple community forum there. Most already try but fail to get replace for free so call " as a good will "

Well my M3 iMac already consider 2 years. For them is not consider new. I do go back Apple community side check seem like more and more M series iMac user encounter this line issue appear on their imac screen. Some claim " maybe those encounter are having the bad batches of iMac " I don't know as some using for 2 years so far claim no lines appear. Perhaps this is why Apple don't come out recall program so call fixing the problem. TO them unless is entire M series iMac users encounter this issue. This is how I feel.

Nevertheless, I doubt is due to " some bad batches of iMac been produce. " As i check around the number of M series users from M1 now to M3 already feedback upon using just after one year or so , Lines appear on the screen. All also claim they never accidentally drop the iMac or knock the iMac. Or even have any liquid happen accidentally spill on it.

Just appear like that suddenly...

 

[kagharaht]

I bought the iMac M3 full spec when it came out. It's on 24/7 and screen does sleep after 10 min. I use this daily for 6 or more hours daily. So far no issue with the screen. Seems to be more iMac M1 posting on that Apple community forum.

 

[Retroworldnews]

I bought the iMac M3 full spec when it came out. It's on 24/7 and screen does sleep after 10 min. I use this daily for 6 or more hours daily. So far no issue with the screen. Seems to be more iMac M1 posting on that Apple community forum.

Me too, I Only put to Sleep when not using. Literally I using it hours daily. Work, see Youtube videos. I never play games as mention. Just like that after 2 years suddenly lines appear at the bottom. Sometimes Flickering , sometimes don't only show lines.

 

[kagharaht]

Me too, I Only put to Sleep when not using. Literally I using it hours daily. Work, see Youtube videos. I never play games as mention. Just like that after 2 years suddenly lines appear at the bottom. Sometimes Flickering , sometimes don't only show lines.

If your M3 iMac is starting to do what those M1 iMac are doing, then it's just a matter of time for it to fully go bad. It's usually the 2 year mark based on the comments from that community forum. Sadly I'm too deep into the ecosystem. If mine dies at least I've been paying AppleCare extended on it so it will get fixed or replaced if it happens.

 

[Retroworldnews]

If your M3 iMac is starting to do what those M1 iMac are doing, then it's just a matter of time for it to fully go bad. It's usually the 2 year mark based on the comments from that community forum. Sadly I'm too deep into the ecosystem. If mine dies at least I've been paying AppleCare extended on it so it will get fixed or replaced if it happens.

As mention even you replace the screen, the line problems will come back after near 2 years of using it. Is the design flaws come M series iMac. I also own the older iMac. Still working the screen only got " pinkish hue " around but it " ok " at least it last over 2 years or so. Some folks also do mention this ' pinkish hue " on older iMac.

 

[TwoH]

It's strange for me to have still never come across this issue personally. I've worked on several hundreds of the M1 and M3 series and have never witnessed any with this issue.

Only issue I've had with these models which might be happening in transit - is that quite a few of the come in with a curved chassis, which also bends the screen.

 

[Retroworldnews]

It's strange for me to have still never come across this issue personally. I've worked on several hundreds of the M1 and M3 series and have never witnessed any with this issue.

Only issue I've had with these models which might be happening in transit - is that quite a few of the come in with a curved chassis, which also bends the screen.

Well it will happen. As mention " maybe due to some bad batches , unlucky I got it and also many others " In fact Mac Rumours it self do write an article on M1 iMac users suddenly have lines appear. I never know MacRumours have written about it after I go search around why suddenly iMac have lines appear. Than I discover it also a lot feedback on official Apple community forum too.