Cannot change Screen Brightness Lock

Since there is not an NVRAM or SMC reset on any M1 mac, the above option will not work.

The lock is caused when the System Preferences –> Displays –> Presets is set to something other than "Apple Display" or "Apple XDR Display" depending on your device or model.

Setting this to the correct Apple preset will allow Automatic Dimming and brightness controls to work properly again. Any of the presets below the line will cause the controls to be locked.

Hope this helps.

Thanks for posting in the Apple Support Communities humbertobarbosa,

We understand you're unable to adjust the screen brightness of your Mac using the keyboard, and see a padlock where you would normally expect to see the brightness level.

If you haven't yet, restart your Mac from the Apple menu, and test to see whether there's any change.

Should the behavior persist, try performing an NVRAM reset. This is a small allocation of memory that stores settings related to the display. The Following page provides additional information, and explains how to perform it: Reset NVRAM or PRAM on your Mac

Cheers!

I had this problem, but why is it that when I want to use lets say the photography preset, that it doesn't allow for brightness changes? this is quite frustrating not being able to change it with most of the display color profiles.