iMac M1 screen showing horizontal lines and extreme overheating at top left corner of screen

Question

Level 1

4 points

iMac M1 screen showing horizontal lines and extreme overheating at top left corner of screen

Hi everyone,

I own an iMac M1, and awhile back I started seeing horizontal lines on the display, along with extreme overheating at the top left corner of the screen. It becomes so hot that it’s almost untouchable after a while, and you can actually get burned if you accidentally touch the corner.

The issue started around January 2025. The iMac has been carefully used, with no damage, and performs normally otherwise. When I connect an external display, everything works fine. This suggests the problem lies within the built-in screen assembly or internal display cable.

After visiting the Apple Store at Marina Bay Sands (Singapore), the staff confirmed it appears to be an internal hardware issue related to the display unit. I’ve also spoken to Apple Support, and my case has been escalated for internal review.

I’m posting this to see if other M1 iMac users still or have expereinced the same overheating and display line issue, and whether you received any resolution from Apple. It seems to be a recurring problem discussed widely online.

Attaching a photo for reference.

iMac 24″, macOS 14.6

Posted on Nov 8, 2025 1:47 AM

Reply

Answer 1

-g

Level 4

3,365 points

Nov 8, 2025 8:20 AM in response to sundar93

try a google search: IMAC SCREEN ISSUES

with symptoms like "extreme overheating at top left corner of screen" i would turn off the unit and immediately contact Apple -- ask them how to proceed -- make sure you get a Case Number and that your concern is accurately quoted...

if someone tells you it is okay to run your machine for tests -- make sure you get their name and ask for 2nd level support before following that advice -- you will probably have to take it to an Apple Store, let them do the tests...

Reply