Persistent horizontal lines appear on iMac screen

Good point. I always get AppleCare on all my Apple devices. I've looked around other sites and forums, like Reddit. No one has talked about this so perhaps you are right. It's just not a big a deal to justify action against Apple.

I am having the same problem. I've had this iMac more than two years. The lines start to appear recently and never disppear. I suspect it is related to the mac os upgrade however as I couldn't revert the os back to its original.

Hopefully Apple staff could give us some clue why would this happen. In the last 15 years, I used so many Apple Macs and never ever had such issue before.

@cristobal2

Has it returned? Have you increased the brightness to 60% or more? Perhaps it's triggered when things heat up inside and the board experience thermal expansion and contraction causing the CPU/GPU SOC to fail because of heating up, cooling down reaction?

The same thing happened to me. I have an IMac M1 purchased in January 2021 in Italy. It happened a little after the warranty ended. Exactly as others here have mentioned. It's unbelievable that the only solution is to buy a screen that has the value of a macMini. I will never buy an IMac again.

zardoz73 wrote:

Apple, fix this. When people bring these 2021 M1 iMacs into the store, fix them for free. It's really lame to get just two years out of this computer, when it clearly can go for several more.

Remember, Apple isn't here. They probably won't see your request, and if they do, they won't respond to you here. This is a user-to-user forum.

I am sure somebody must have provided a feedback link. If not: Product Feedback - Apple

I have the same problem with my iMac M1 (2 USB-C ports) bought in Singapore in September 2021 (model number ending with ZP/A - Southeast Asia). The problem appeared yesterday.

So the symptoms are the same: iMac M1, 2 years in use, mostly Asia manufactured models affected.

I am having the same issue as you all. I was using my iMac today and suddenly this grey bar has appeared on the bottom part of the display (see picture). I've tried restarting, updating but it's still there. When connected to an external display there is no grey bar on that.

I bought my iMac in August 2021 so just over 2 years. This cannot be a coincidence that this is happening to all our iMacs that are over 2 years. This is either caused by a recent software update or this is a hardware failure. Either way this is unacceptable for an Apple product. These iMacs should last a minimum of 5 years before any problems.

I am going to contact Apple support and see what they say. I refuse to replace the display for > £600 when this issue can return again.

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?

I have the same problem.

iMac 24" 2021 was bought in Aug 2021. Now with just two and a half years.

Lines started to appear near the bottom of the screen and went up until fill up about 70% of the screen with ghosts of the dock app icons at the bottom.

My second monitor is working perfectly.

Very strange...

Hardware specifications:

Model: iMac

Model identifier: iMac21,1

Model number: MGPD3Y/A

Chip: Apple M1

Total number of cores: 8 (4 for performance and 4 for efficiency)

Memory: 8 GB

System firmware version: 10151.61.4

OS loader version: 10151.61.4

Serial number (system): C02FN0YXQ6W2

Hardware UUID: 56C4E9C3-1E32-574A-825A-AACC871742F1

Provisioning UDID: 00008103-001465AA2ED9001E

Activation lock status: Active

To get the Model Number go to “System Settings > General > Informations > System Report > Hardware > Hardware Specifications“.

Tough to tell what is there...

The new iMac's interior is dominated by two huge metal plates. What are those for?

Almost all of the silicon is concentrated into narrow horizontal strips at the top (the display board) and bottom (main logic board).

Can somebody test if the temp drops or lines lessen if NightShade is ON?

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.

Same problem here. Mine started all of a sudden 10 days ago when those horizontal lines appeared on my screen. The weird part is when they first appeared it also had a cluster of red and black pixels top right.

After restarting and shutting it down several times it did nothing. Only after leaving it without being connected to the power cable for more than two days the cluster disappeared. But the lines are still there.

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?

Understood, just trying to help with this part of the post...

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.