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My laptop no longer adjusts screen brightness

Makam Mythily (AQUENT LLC) 25 Reputation points Microsoft External Staff
2025-11-18T15:20:42.5166667+00:00

After recent Windows updates, my laptop no longer adjusts screen brightness automatically when the lighting changes.

Windows for home | Windows 11 | Desktop, Start, and personalization | Desktop

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  1. Gui 100 Reputation points Microsoft Employee Moderator
    2025-11-18T15:21:35.32+00:00

    This happens because the Ambient Light Sensor (ALS) isn’t working correctly due to a timing conflict in the Display Enhancement Service on Windows 11 24H2 and 25H2. After a reboot, Auto-Brightness is turned on but won’t respond until another brightness-related action occurs. Microsoft is aware of the issue and plan to release the fix in an upcoming Windows update.

     

    Temporary Fix

    You can restore Auto-Brightness by performing one of these actions:

    • Adjust the brightness slider manually or press brightness hot key (e.g., F5 or F6).
    • Plug or unplug your device (switch AC/DC power state).
    • Turn Battery Saver on or off.
    • Put the device to sleep while on battery power.

    Any of these steps will reactivate the Ambient Light Sensor and make Auto-Brightness work again.

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  1. Q&A Assist
    2025-11-18T15:21:12.0333333+00:00
    AI generated content. This question contains an answer created with AI from Q&A Assist. Learn more

    If your laptop is no longer adjusting screen brightness automatically after recent Windows updates, you can try the following steps to troubleshoot the issue:

    1. Check Ambient Light Sensor: Ensure that your laptop has an ambient light sensor (ALS). You can verify this by going to Display settings and looking for the option "Change brightness automatically when lighting changes". Make sure this option is checked.
    2. Update Display Drivers: Sometimes, outdated or incompatible display drivers can cause issues with adaptive brightness. Check for updates to your display drivers through Device Manager or the manufacturer's website.
    3. Adjust Power Settings: Go to Settings > System > Power & sleep and ensure that your power plan settings allow for adaptive brightness. You can also check the Advanced power settings to ensure that adaptive brightness is enabled.
    4. Registry Settings: If you are comfortable with editing the registry, you can check the registry settings for adaptive brightness. Look for the keys related to adaptive brightness and ensure they are set correctly.
    5. Run Windows Troubleshooter: Use the built-in Windows troubleshooter for hardware and devices to detect and fix issues automatically.
    6. Re-enable Adaptive Brightness: Sometimes toggling the adaptive brightness setting off and on again can reset the functionality. You can find this option in the Display settings.

    If these steps do not resolve the issue, you may want to consider rolling back the recent updates or seeking further assistance from Microsoft support.

    References:

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