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macrumors bot
Original poster
Apr 12, 2001

Apple today shared a new support document outlining a warning symbol that can show up on the MacBook Pro with Liquid Retina XDR Display or the Pro Display XDR when the screen is running too hot, leading to brightness being diminished.


Apple explains that a caution symbol in the menu bar or Display menu in Control Center on a 2021 MacBook Pro or an Apple Pro Display XDR means the display is in low power mode and "using limited brightness."

This situation can occur if the ambient temperature of the room is high and if bright content has been playing for an extended period of time. Apple offer several solutions for those who see the warning, including lowering the temperature of the room and temporarily putting a Mac to sleep to allow it to cool.
  • On MacBook Pro with Liquid Retina XDR display, quit any apps that could be consuming significant system resources.
  • Use the Apple XDR Display or Pro Display XDR reference mode unless your current workflow requires a specific reference mode.
  • Lower the ambient temperature of the room.
  • Close or hide any windows with HDR content.
  • Choose Apple menu  > Sleep to put your Mac to sleep. Let your display cool down for 5-10 minutes, then press any key on the keyboard to wake your Mac.
Apple says that users who see this problem continually when the ambient temperature of the room is under 77 degrees Fahrenheit should contact Apple Support for help.

Article Link: Apple Says Pro Display XDR and 2021 MacBook Pro Can Experience Limited Brightness in High Temperatures


macrumors 6502a
May 24, 2010
Only ever got the caution symbol on an Apple device once, and I knew I was torturing the device under direct sunlight in sweltering heat. This is a reasonable precaution for extreme situations, and it’s clear it doesn’t get triggered easily or often.


macrumors regular
Jan 16, 2008
In a perfect world you should be able to use whatever setting you paid for, but blasting all those nits into your eyeball over a long periods is really a bad idea.
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macrumors 6502a
Jul 8, 2014
Northamptonshire, United Kingdom
This is just physics, those mini LED’s will generate a lot of heat when at a high brightness and could potentially damage themselves.

LG OLED TV’s are the same you could buy a cheaper model which would be dimmer, or you could buy the more expensive EVO models which have a heat sink attached to the back of the panel allowing the pixels to be driven brighter.

If Apple were to attach a heat sink to the screen the MacBook would probably be too thick and probably top heavy reducing it’s stability.

That being said I bet even at a dimmed brightness this thing is still brighter than most other laptops on the market.


macrumors 6502a
Oct 15, 2011
Apple designs their products to be used in 23°C despite mentioning the 35°C in the specs.

"..ambient temperature of the room is high"
So what is high ambient temperature? Every review of a product testing thermal performance I have seen does it in a air-conditioned room, and doesn't even mention ambient temperature, but I assume its around 23°C.

Its 37°C inside today and I expect products to be engineered with enough cooling to work at its best levels at up to, at least, 40°C.
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