Persistent horizontal lines appear on iMac screen

Hey guys,

I posted here a few months ago about my problem, same way as yours, on an iMac M1. Started in august, in December the situation worsened, and in February, beyond the lines, the screen started to get VERY hot. During this time, I contacted Apple several times to report what was happening, even though they refused to repair it. I took photos and videos and documented everything, talked about this discussion and other reports. The situation only changed when I reported that the screen was getting very hot and was passed to a senior support and after a few days took the display for evaluation. It took about six months, many contacts, persistence and patience, two in-person evaluations, and luck to be served by attentive people. But it worked out: in March, I was informed that they granted me an exception (they emphasized this point) and approved the replacement of the display free of charge. I don't know if it was luck, the way things work in Brazil and customer service, or some genuine concern for customers, but it worked out. Keep reporting. I don't know if the feedback really works, but maybe talking to people will. Good luck!

haixin512 wrote:

Keeping contact apple feedback with the info below: (i do it once a week now)

Product Feedback - Apple

+1 It is a good idea to keep sending feedback and to call.

The kicker here is, that Apple does not make the display panels. They out source the display panels from third-party suppliers like Samsung, LG and others.

As I recall, something similar happen to some displays panels in the late 2005 and early 2006 iMac's. After a couple of years, some of the display panels starting getting multiplying vertical lines. Sadly it took Apple another year to settle-up with the display manufacture and acquire enough replacement displays to start an Extended Service program.

One way you can prove or disprove that's its hardware or software is to erase the drive and install a new system. Do not migrate your user data to it for this test. If the problem appears then it's hardware and not 3rd party software issue.

If gone then it's software and you should manually restore the contents of your Music, Pictures, Documents and Desktop folders from your latest Time Machine backup to the new user account (which should be an admin account and can be your original user name and password.

Then you should reinstall all of your 3rd party software. NOTE: be sure to note all of the activation codes for those 3rd party apps that require them.

Also do not installed and run any "cleaning", "optimizing", "speed-up", anti-virus or VPN apps on your Mac on your new installation. A VPN is OK if it's required by your employer, bank or school.

If it's hardware related you'll have to make a decision as to how to address it. A possible alternative is to get an inexpensive 27 inch monitor and run it along with the damaged monitor and use it as your primary monitor.

Just some food for thought.

Addendum: all of this requires you to have a full and current backup of your boot drive with Time Machine or some other backup app.

If there ever is a fix it will be announced here: Apple Service Programs - Apple Support

So make a bookmark of that site and check it frequently. Also anyone who has this problem and has not taken it into an Apple Genius bar should so they know the extent of the problem.

I have this issue, M1 iMac purchased in Tokyo, Japan in 2022. It seems to be a problem in Asian countries mostly. I was working on a simple Google Doc, rubbed my eyes, and when I looked again the black lines appeared. Right in the center third of the screen. It's extremely annoying. And of course I don't have Apple Care...

This has been a noted issue on the iFixit site:

****

It does not actually seem to be that difficult to replace the screen. Has anyone tried to replace the screen themselves? There are a number of videos on YouTube for this: https://www.youtube.com/watch?v=uBjMr--idKo

But I'm wondering if I should just get an external monitor instead. It's very frustrating. I've been bragging to my friends about this M1 iMac for years now. "Buy a Mac," I say. "They're pricey but they'll last at least five years!" I am eating my words now. I have an M2 MacBook Pro that I also really like...am I going to have this problem with it in two years?

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.

[Edited by Moderator]

MacBooks with FlexGate have similar problems. In the MacBook, this is caused by the LVDS cable, which is fixed to the PCB of the lcd assembly and not easily replaceable.

However, the LVDS cable in the iMac can be replaced. Has anyone had experience with this or replaced this cable before?https://www.ebay.nl/itm/255809013613?mkcid=16&mkevt=1&mkrid=1346-175129-2357-0&ssspo=9_Kc3GPRQIS&sssrc=4429486&ssuid=2ViFqcZVSqK&var=&widget_ver=artemis&media=COPY).

Hey everyone, when I got in touch with a senior advisor to escalate the case, they told me there was NO record of this being a widespread issue.

I asked if there’s a way for everyone experiencing this to report the problem directly, and the advisor pointed me to the Apple Feedback page. If you’re dealing with this too, I’d suggest submitting your feedback there. The more people report it, the better chance Apple might take notice and address it.

Hello everyone,

I’m adding my voice to the growing number of iMac M1 owners experiencing persistent horizontal lines across the display.

• My iMac is the 24-inch M1 (2021).
• The lines appeared suddenly and are worsening over time.
• When I connect to an external monitor, the issue does not appear, which suggests it’s a built-in display hardware fault and not a GPU/software issue.
• The lines do not appear when taking a screenshot, which suggest according to the apple advisor on the chat that it is a hardware and not a software issue
• I’ve seen many others here and on Reddit/MacRumors describing the exact same problem, often 1.5–2 years after purchase.

This seems to be a widespread defect, not accidental damage. It would be great if Apple could officially acknowledge this and provide support—whether through a repair program or extended coverage.

Has anyone here successfully escalated this with Apple Support and received a repair (in or out of warranty)? If so, could you share how you approached it?

Thanks for any advice, and I hope Apple is listening to the many of us dealing with the same display failure.

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.

Not a software issue. My workaround is using an external monitor, which works fine. Also I can share the screen to my smart TV, which also looks fine.

No, this is a hardware issue with the iMac itself.

I bought an imac m1 2021 and black lines started appearing then eventually this weird blotch of purple color started showing on the top left hand screen. Then it gradually got worst to the whole screen is black and the computer is unusable. I also noticed a burn mark up in tge left side of the screen where the putple blotches of color was. I just read someones post that took his computer with same problems to a repair guy to get a diagnosis of it and said something like there is a faulty cable that overheats so this explains it. Im really angry as Apple told me that can’t do anything because it’s out of warranty. I’ve been using Apple for decades and I always take care of my equipment. I use it for work feel really cheated because this computer was defected from the beginning. There was so many issues.

Jotap62 wrote:

Dear Old Toad,

According to Apple support, it's an LCD malfunction and the only solution is to replace it.

So it's not a software problem.

It's a hardware problem.

That's already established.

Then maybe the most economical path forward might be an external 3rd party monitor. When you upgrade to a new Mac it can be a second monitor for that Mac.

There might be a connection between auto-adjustment of brightness and the onset of flickering. My iMac first had the flickering one week ago. I turned it off and on. The flickering disappeared, but a black line persists. Since then, the flickering appeared a few times more. It seemed start when there's a change in environment light. For instance, I pulled down the curtain. My room became darker. The brightness of the display changed (I had auto-adjustment of brightness on). Also appeared flickering. I then disabled auto-adjustment of brightness. Flickering hasn't re-appeared since. Just to share my observation, in case it might be useful.

My advice is to turn off the LCD lighting on your iMac (set it to 1).

By reducing the brightness you'll be able to see that the temperature at the top of the LCD becomes normal and the worry about over-temperature will disappear.

Then buy a new external monitor.

There are very good monitors available relatively cheaply.

I worked like this for almost a year when my iMac was broken and without any problems.

It's the same as having a (very expensive) Mac mini...

But at least you can keep working until Apple sort it out.