Why Does the Keyboard Backlight Change?
MacBook Pro and MacBook Air laptops are equipped with an ambient light sensor (the same sensor used to adjust your screen brightness). By default, macOS uses this sensor to automatically illuminate the keyboard backlight when you are in a dark room and turn it off when you are in a brightly lit environment.
While this is a helpful feature, the sensor can sometimes be overly sensitive. If you are sitting near a window on a partly cloudy day, or if you frequently shift your position under a desk lamp, the keyboard backlight might constantly flicker on and off, which is highly distracting. You can stop this automatic adjustment and lock the backlight to a manual level.
How to Disable Automatic Keyboard Illumination
You can turn off the ambient light sensor’s control over the keyboard in the System Settings.
- Click the Apple Logo in the top-left corner of your Mac’s screen.
- Select System Settings… (or System Preferences on older macOS versions).
- In the left-hand sidebar, scroll down and click on Keyboard.
- Look for the toggle switch labelled Adjust keyboard brightness in low light.
- Toggle the switch to the Off position. (If you are on an older version of macOS, uncheck the box).
How to Manually Control the Backlight:
Now that the automatic sensor is disabled, you must adjust the brightness manually. You can do this by using the dedicated F5 and F6 keys on your physical keyboard (if your Mac has them), or by clicking the Control Center icon in the top-right menu bar, selecting Keyboard Brightness, and dragging the slider to your preferred, permanent level.