Persistent horizontal lines appear on iMac screen

I have two 2021 M1 iMacs having the same issue after +3 years of use. Genius bar offer a US$700 expensive repair option, which I refused to accept. Given my own experience and the threads I read so far, I believe this is a systematic issue rather than an isolated one. As a loyal Apple user, it is sad that it does not seem Apple is taking care of this issue seriously.

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MacOS Sonoma. The day before the lines appeared I used an app called handbrake to convert a DVD to mp4s to put into imovie. Not sure if that could have anything to do with it.

Same thing happened to me. I was using it earlier today and the lines appeared out of nowhere

Update to the Update: After an $830+ bill at Apple Certified Jack Be Click in Kona Hawaii and 4 hours driving back & forth my "repaired" machine was returned inoperable. The proprietor has not returned my call/message. So frustrating.

I'm doing exactly this now. Using a second monitor, and using the Lunar app to turn off the defective main display. Apart from the display, everything else is working as it should.

Same problem for my 2 year old iMac. The horizontal lines appeared shortly after 1 year. I brought to Apple Store and got quoted SGD$950 to repair the screen. The cost is more than half the price of the iMac itself. Hopefully Apple acknowledge this issue and offer repair programmes.

The right corner of my iMac with this issue was also very hot to touch.

I had this issue with the 2 fan version.

The exact same problem just appeared. Reading this thread, i'm affraid...

My macbook pro lasted 8 years and were still perfectly fine. It's such a disappointment from Apple...

Hey - did you manage to find a fix? I cancelled my appointment too, but was told by support that bringing it in for diagnostics may help raise awareness around the issue (I’m located in Singapore)

I've always kept my display at or near half, and never used it at full, and this defect still happened.

so, will Apple take responsibility for this malfunction? because their iMac 24" display only last for two years used. What happen to Apple Studio display, is it have the same problem?

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.

I have the same issue on my 2021 M1 24" iMac since 2023.11. My screen occasionally flickers and there's a black line fixed appearing at the top. The support told me it would cost 20,000 TWD to replace it. They suggested either using an external monitor or purchasing the latest M3 model would be more cost-effective.

I found the issues all are from after using 2 years.

Since there have been numerous reports of the same issue, shouldn't they initiate a recall to inspect the product problem? 20,000 TWD is already half the price of buying a new one.