Persistent horizontal lines appear on iMac screen

Just had this problem start yesterday. I think Apple did this on purpose. Reminds me of when they did this with the iPhone battery a few years after downloading an update that was rigged to ruin the battery. My iMac is just barely two years old! What a rip-off! Maybe Apple needs another lawsuit?

Alpha_Centauri_Prime wrote:

I feel this is overheating issue. The top right corner feels very hot when touched (Anyone observed this?). 1. The logic board is at bottom. what device is there at top right corner? The lines come and go.

Hi! I don't experience this overheating on my machine. The top left and top right corners are equally warm for me. The only warmer place is near the power cable. But I don't use any CPU-heavy apps so I heard fans only a few times during all my usage of this iMac. So I don't think overheating is the reason.

Here are my latest observations regarding this issue.

For the past couple of months, there has been a small, green dot in the upper most, right-hand top corner. From what I have discovered, it is the microphone light. It means that the microphone is on, from what I gather. I haven’t found a way to turn it off. Does this mean that the microphone is on and it is recording? Does anyone know anything about this light? This light appeared after the first of the two major updates. So, maybe in September?

My gray lines seemed to appear out of nowhere after the second major update on Feb.17-18. At first they covered the middle of the screen, and have now dropped down to the bottom half. The odd thing is, is that they move with the sound of whatever I have making noise on the computer. It’s like the bars are showing sound levels. But, it also does this with external sounds, like my space heater. I think we are on record, here.

Has anyone else noticed this?

Whatever be the culprit, once it comes, it'll never go... and will only keep expanding all thru the monitor. Mine keeps juggling between half the screen space and one-fourth. I've already ordered an external monitor as back-up to continue using my iMac M1 model with horizontal lines, as over a period of time u will get EYE STRAIN working on it seeing those horizontal lines flicker all thru the day :(

Hi there,

I'm having the same problem with my iMac. While I'm on a video call, my screen suddenly doesn't look right, like it's covered with a screen. Tried restarting, updating the system, and safe mode to no avail.

I bought it in the UK in September 2021. The specific model is MGPH3B/A. iMac m1 4 ports.

I was originally going to follow the advice of Apple customer service and take it to an Apple store. Thank you everyone for your comments, which saved me a time-consuming and labor-intensive journey. Replacing the screen is really expensive. I'll probably look for any replacement monitors with a similar resolution to the iMac.

Hope to see any updates.

There is no fix. The only solution is to replace the screen. When I bought the imac in June 2021 since it was a new product on the market I made an insurance plan for 5 years that costed me 150€. Last month the store replaced the screen with no additional charges.

This is the exact same thing that’s happening to me right now. I thought it was just from the heat, but oddly enough, after turning my computer on after 2 minutes, the upper right corner is already HEATING UP. But it’s only on that specific corner???

UPDATE:

Got in touch with Apple Support; they asked me to take the backup of the Mac and start it in safe mode. Since the issue continued, I reinstalled macOS (Sonoma 14.4.1), but the problem persists.

Then Apple Support asked me to book a reservation at the Apple Store for their technician to check the iMac. They couldn’t check the price estimated for the screen repair. Of course I don't have AppleCare.

I am getting an inexpensive Samsung 1080p monitor and an Amazon USB-C Digital AV Multiport Adapter. I’ll connect the external monitor and continue using the iMac with the lowest brightness.

nope, if you tried replace it from outside apple service center or another AASP (cheaper price) you will loose true tone feature (on your new display that you replace) it's because need some system configuration from the Apple (it's apple secret) and it will happen and all Apple product (with the display of course), and something you need to consider is, will this happen again in two year after you are replace it?

can you multiple claim on it? what if your new display will malfunction again in two year after you claimed on your first? are you sure i'ts a good one or it's just like your display before (normal display and boom) there you go, it happen again ?

Same issue here. iMac M1 2021, pre-ordered it. I've taken the best care of it, after all, it's just sitting on a desk. Seems like the display just spontaneously failed. This happened a week ago.

I don't know if I should replace the screen, because what if it happens again? I'm afraid it's the problem with the design of the screen and/or the computer itself, therefore a replacement may not completely fix the issue in the future.

Can we please get a response from Apple? This doesn't seem like it's an isolated issue, as evident from this thread. A lot of people are having this same problem. This makes me think it's a problem with the design or the manufacturing process.

My Imac which i bought in August 2021 started showing this grey flickering background from about halfway of the screen to the bottom. I have done diagnostics and there is no software or physical damage to it. I am reviewing for my exams and this is so very untimely and very annoying to put it lightly. I trust apple products so much that all devices are apple. What can you do about this? We have all been here asking for your help. This is a a faulty model from your end not ours. I have been very careful in using my imac for the 2.5 years that i have it.

I am facing the same issue, same model (M1 iMac 24", 2 ports), about 2 years old (purchased Feb 2022).

Hope Apple will do something about it. It is just unacceptable for us to pay an extra 700 just to extend the usage. Does that mean, for me to continue using this device, I have to pay 700 every 2 years?