Auto-brightness stuck at half on MacBook Air M1 despite manual adjustments

Question

Auto-brightness stuck at half on MacBook Air M1 despite manual adjustments

I'm having issues with my MacBook Air M1. It seems that auto-brightness got stuck at a certain level (around half of the brightness slider) and no matter what the conditions are it won't decrease. I've been trying to 'teach' him that I'm comfortable with lower brightness by manually adjusting the levels but whenever I reset the option (turning off and on) it jumps back to the position it remembered in the past. My light sensor works fine, I can shine my torch at it and the brightness goes up instantly.

I have to point out that it worked well in the past but after one evening when I was watching a movie I cranked up the brightness a little and after that it got messed up.

Basically I'm looking for a way to factory reset all the auto-brightness settings (including sensor 'memory').

Thank you for your help.

[Re-Titled by Moderator]

Original Title: auto-brightness stuck

MacBook Air 13″, macOS 26.0

Posted on Oct 4, 2025 5:35 AM

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Answer 1

Oct 4, 2025 2:14 PM in response to Tom_Blaszkiewicz

Within the Terminal app run the following command to clear the NVRAM (aka PRAM):

sudo  nvram  -c

This command will prompt you for your admin password. Nothing will appear on screen as you type the password, so press the "Return" key to submit the password. This command may mention that certain items could not be cleared such as the Computer Name which is normal. As long as the command itself has no error, you will need to reboot the computer so that the system & macOS pull the default values from the NVRAM/PRAM.

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Answer 2

Oct 5, 2025 9:24 AM in response to Tom_Blaszkiewicz

You can try creating a new macOS user account. Log out of the main user account & log into the new user account. If it works in the new account, then there is some sort of issue with your main user account.

The only other simple test is by testing with a clean install of macOS (erasing the Mac followed by reinstalling macOS). Testing must be done prior to installing any third party apps or migrating/restoring from a backup.

I doubt this will help, but you can try a DFU Firmware Revive which resets the security enclave chip & system firmware.....it should not affect the data if the process successfully completes. However, this process requires access to another Mac running macOS 26.x Tahoe (perhaps macOS 15.x Sequoia as well).

How to revive or restore Mac firmware - Apple Support

Otherwise, you likely have a hardware issue which will need to be repaired.

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Answer 3

Oct 4, 2025 9:39 AM in response to Tom_Blaszkiewicz

Not aware of any direct way to do that. You could try booting in safe mode, which disables 3rd party extensions and performs some system cleanup. Then reboot normally.

Start up your Mac in safe mode - Apple Support

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Answer 4

Oct 7, 2025 9:15 AM in response to Tom_Blaszkiewicz

"Auto" means "Auto". If you want to set it at some specific level, just turn auto off, and adjust manually.

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Answer 5

Oct 5, 2025 8:07 AM in response to HWTech

I did the following:

Turned off auto-brightness and true tone.
Reset the NVRAM.
Restarted the system.
Turned auto-brightness and true tone on.

Unfortunately nothing has changed. The sensor doesn't react when I cover it with my hand (still at half the slider) but it goes up when I shine a light at it.

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Answer 6

Oct 4, 2025 12:43 PM in response to neuroanatomist

Thanks but that didn't change much unfortunately.

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