Blooming cursor on dark backgrounds (M4 Max MacBook Pro)

[restless_honey]

Hi all!
I recently noticed something on my new macbook that I’m not sure is a defect or just a characteristic of the mini-LED XDR display.

On dark backgrounds, moving the mouse creates a strange glow or halo effect around it. It’s noticeable at different brightness levels and in different lighting conditions. It happens in all apps and on any dark background (it's less visible on black)
If I switch the display settings from Apple XDR Display (P3-1600 nits) to Apple Display (P3-600 nits) the effect almost disappears. Changing refresh rates (ProMotion → 60Hz, or opposite) also reduces it. Switching these same modes in the opposite direction also works. Basically, it seems it doesn’t really matter which mode you switch to or from, what matters is that the display settings are changed.

But! The effect returns after restarting the Mac.

Things I’ve tried:
Checked with another user account
Safe Mode
Recovery Mode (background is black, so effect is less pronounced)
MacOS updating to latest Sequoia
So nothing has changed

The macbook has never been dropped or damaged, and I handle it very carefully. I’ve also seen discussions here and Apple forum suggesting this might be a feature of M4 mini-LED displays, but some people had their machines replaced.

I recorded a video to show the issue. At the beginning of the video, you can see the problem right after turning on or restarting the Mac, and later you can see it after switching any of the modes described above, it's almost disappeared. Of course, the phone camera exaggerates it a bit, but still.

Have you experienced this maybe?

 

[Eric_WVGG]

Yes, that's pretty much how Micro-LED backlights work.

A normal backlight is a white panel that spans the entire screen, behind the matrix that makes colors and blacks. It's always on; that's why typical screens (including current Macbook Air and Studio Display) are never 100% black — there's always a screen-sized flashlight behind the LCD. (turn the brightness on one of those laptops all the way down to see what it would look like without the backlight)

Macbook Pros since M1 instead have an array of white LEDs that are spaced about 1 inch apart; there's about a hundred or so. They are selectively turned on based on what's going on the screen. That bloom is a single microLED lighting up the cursor.

I actually damaged one of the micro-LEDs on my M1 Macbook Pro by applying too much pressure while cleaning the screen, now there's a faint yellow spot on the screen there. I gave it to my parents and upgraded to an M3 Max. They say they don't even notice it, so… ¯\_(ツ)_/¯

I basically never notice the blooming, and while imperfect, find it hugely preferable to standard LCD. I’m looking at a Studio Display and my Macbook Pro right now, the Studio Display basically looks like crap compared to it. The bloom is a small price to pay.

OLED is the next step, but I guess that's still too expensive and problematic (burn-in) for Macs.

 

[Basic75]

Yes, that's pretty much how Micro-LED backlights work.

It's Mini LED.

Micro LED is a different technology without backlights, like OLED.

 

[restless_honey]

Yes, that's pretty much how Micro-LED backlights work.

A normal backlight is a white panel that spans the entire screen, behind the matrix that makes colors and blacks. It's always on; that's why typical screens (including current Macbook Air and Studio Display) are never 100% black — there's always a screen-sized flashlight behind the LCD. (turn the brightness on one of those laptops all the way down to see what it would look like without the backlight)

Macbook Pros since M1 instead have an array of white LEDs that are spaced about 1 inch apart; there's about a hundred or so. They are selectively turned on based on what's going on the screen. That bloom is a single microLED lighting up the cursor.

I actually damaged one of the micro-LEDs on my M1 Macbook Pro by applying too much pressure while cleaning the screen, now there's a faint yellow spot on the screen there. I gave it to my parents and upgraded to an M3 Max. They say they don't even notice it, so… ¯\_(ツ)_/¯

I basically never notice the blooming, and while imperfect, find it hugely preferable to standard LCD. I’m looking at a Studio Display and my Macbook Pro right now, the Studio Display basically looks like crap compared to it. The bloom is a small price to pay.

OLED is the next step, but I guess that's still too expensive and problematic (burn-in) for Macs.

Yeah that makes sense and explains the blooming.

What still puzzles me is the mode-switch behavior, after toggling the settings, that blooming trail is almost gone until the next reboot. That feels more like a software issue in the dimming algorithm rather than pure hardware limits.. idk

I guess I’m just worried a lot because it might be a defect, especially considering the cost of macbook. On the other hand, it’s unlikely they would replace it anyway, and I’m not sure diagnostic and whole process worth the stress and waiting.
I just want to figure out, should I actually worry about, or should I just let it go.

And I’m really sorry to hear that you had that experience with your screen!! Every time I learning something new abot apple screens and displays.

In any case, thank you so much for your reply.

 

[Eric_WVGG]

It's Mini LED.

Micro LED is a different technology without backlights, like OLED.

Thanks. I can't keep these dumb names straight.