iMac 24″ M1 (2021) – Horizontal White Line, Discolouration, and Overheating on Display

Hello everyone,

I’m facing a display issue with my iMac 24″ M1 (2021). A few days ago, I noticed a horizontal white line and a slight discolouration or shade running across the middle of the screen. The upper-left section of the display also gets extremely hot during normal use.

At first, I tried taking a screenshot to show the issue, but I later realised that the problem doesn’t appear in the screenshot — it’s visible only on the physical display. When I viewed the screenshot on my iPhone, the screen looked completely normal.

I also searched the Apple Community forums and found that many other users have reported similar issues with this same iMac model (M1, 2021).

My iMac is out of warranty (purchased on 22 October 2021), but I sincerely hope Apple will review this as a recurring issue and offer some support or service option for affected customers.

Has anyone else experienced this same issue recently?

If yes, did you receive any official response or repair assistance from Apple?

I have already contacted Apple Support and shared photos taken on my phone that clearly show the problem. Any advice or shared experiences from others would be really appreciated.

Thank you!

Model: iMac 24″ M1 (2021)

Purchased: 22 October 2021

Location: India

macOS: Tahoe 26.0.1