Thin red border on screen

KT010 wrote:

I just wiped my keyboard (on my new macbook) while watching a video and a thin red border line appeared. I saw this boarder on my older macbook air(2017) as well. I thought it happened because the laptop was older, but this macbook is brand new.

All other answers point to restarting the macbook or look into screen (sharing) preferences on the macbook but they do not fix the problem. The ultra thin red border line appears only when I watch netflix/Disney+ in full screen and in any other cases it is not there. So there is no physical damage.

I accidentally turned it on by wiping my keyboard clean so it must be possible to turn it of using the same or reversed keyboard combinations.

Please help!

This sounds like the red frame that you see while you adjust the Arrangement in dual displays.

Do you have a display adapter plugged in, run dual displays or have the >System Preferences> Displays>Arrangement tab open.

If this is an Intel Mac—Try resetting NVRAM/PRAM http://support.apple.com/kb/ht1379

if no resolve Try a SafeBoot https://support.apple.com/en-us/HT201262 to clear system caches

Use external monitors with your Mac - Apple Support

Use multiple displays with your Mac - Apple Support