These horizontal lines at the bottom of the screen appear on an iMac M1. Not limited to the dock. They do not show when I access this iMac with a remote tool (Anydesk). Has anybody ever seen these before?
If they don’t show up when screen sharing or when doing a screen capture, then they are almost certainly the result of damage to the LCD panel.
Time for a trip to a repair shop. And a possibly expensive display (or complete top-case) replacement if it’s out of warranty.
An independent repair shop might be able to fix it without a complete top-case replacement, depending on what is actually broken. It might, for example, be a small chip or connector cable. But Apple and authorized repair people don’t do repairs - they only replace large subassemblies, which can cost a lot more than necessary.
2 Likes
It now becomes clear that I’m not alone, there’s a 17 page long discussion on Apple’s support forums, with a significant number of cases mentioned, see here: Persistent horizontal lines appear on iMa… - Apple Community Apple has apparently chosen to lock this discussion.
This answer (click) gives a technical explanation of the fault, not much help for those affected though.
Possibly now a story for @ace ?
FWIW, here’s a corresponding thread from the iFixit forum:
Unfortunately, they don’t have any answers either.
If it is a cable going bad, then I wonder if any of the people at iFixit might be able to create a post describing how to change that cable. Of course, getting a replacement cable may not be possible.