Note: some users report Turnoff Adaptive brightness option from power options, allows them to customize the screen brightness. That’s all, restart your system and check on next login windows allows adjusting screen brightness. Now locate and click each of the following…” Display brightness”, “Dimmed display brightness” and”Enable adaptive brightness”.Ĭhange each of these to the settings you wish, then click the “Apply” button and finally the “OK” button.In this new window click “Display” to open up the listings under it.Click the “Change plan settings” link next to whichever plan you are currently using and then click “ Change advanced power settings“.Go into “Control Panel” and then “Power Options” Or Right-click on the Power icon on the taskbar and select Power Options.Restart windows and check This will fix “can’t adjust brightness ” bug. You Can check And install latest updates from Settings ( Windows + I ) -> Update & Security -> windows update -> And check for updates. If the problem started after install windows 10 version 21H1, then make sure you have installed the latest Cumulative Update, As Microsoft mention: “ Addresses an issue with the brightness controls on some laptops after updating to the Windows Update.