Brightness not working in Windows 11: how to fix it

Applies to: Windows 11 laptops, tablets and desktop PCs, with notes for external monitors. This guide covers a missing slider, keys that don’t respond, brightness stuck at one level and a screen that keeps changing brightness. If the picture flickers or goes blank instead, see screen flickering in Windows 11.

Match your symptom

What you see	Likely cause	Go to
No Brightness slider on a desktop PC	External monitors are controlled from the monitor itself	Fix 2
Slider moves but the external screen doesn’t change	Windows can’t adjust that monitor	Fix 2
Brightness keys do nothing, but the slider works	Function key mode or the maker’s hotkey software	Fix 3
Screen dims in dark scenes or when the room changes	Automatic or content-based brightness	Fix 4
Slider missing or stuck on a laptop’s built-in screen	Display driver missing, generic or damaged	Fix 5
Problem started right after an update	A new driver or update changed something	Fix 6, Known issues

Fix 1: Try both brightness controls

Windows 11 has two places for the same setting, and testing both tells you whether the control or the screen is the problem. Microsoft’s brightness and color page lists them:

1. Select the Network icon on the right side of the taskbar. In the panel that opens, drag the Brightness slider.
2. Open Settings > System > Display and adjust Brightness there.

If one works and the other doesn’t, Windows itself can change brightness, and the fault is in the shortcut you were using. If neither shows a slider, read Fix 2 if you use an external screen, or Fix 5 if this is a laptop. Before going further, restart the PC once. A restart reloads the display driver, and it costs nothing to try.

Fix 2: External monitor? Use its own buttons

If you use a desktop PC, start here. Microsoft states that you might not see the Brightness slider on devices with an external monitor, including desktop PCs, and that you change an external monitor’s brightness with the buttons on the monitor. That’s expected behavior, not a fault.

1. Find the menu or joystick button on the monitor, often on the bottom edge or the back.
2. Open the on-screen menu and look for a brightness or picture section.
3. If brightness can’t be changed there either, check the monitor’s manual. Some picture presets or eco modes can fix brightness at one level; this varies by model and isn’t covered on Microsoft’s page.

On a laptop connected to a second screen, expect the slider to change the built-in display only; Microsoft’s page describes it in terms of the built-in screen, so the external one still needs its own buttons.

Fix 3: Brightness keys do nothing

Laptop brightness keys usually share a top-row key with a function key, so whether a press changes brightness can depend on the Fn key. Microsoft’s brightness page doesn’t cover these keys, so treat the following as general checks rather than official steps:

1. Hold Fn and press the key with the sun icon. If that works, your laptop is set to send function keys by default.
2. Look for an Fn lock key, sometimes marked with a padlock, or a setting in the maker’s utility or the firmware setup that swaps the top row. The name and location differ by brand.
3. Reinstall or update the laptop maker’s hotkey or control software from its support site. On some models, the brightness keys rely on it.
4. Confirm the slider in Fix 1 works. If it does, the keys are the issue, not the display.

If other keys are also unresponsive, the problem is wider than brightness, and our guide to keyboard not working in Windows 11 is the better place to start.

Fix 4: Brightness changes by itself

A screen that dims or brightens without you touching anything is often Windows doing what it’s set to do. Microsoft describes two separate features, and both live in Settings > System > Display under Brightness:

• Brightness based on lighting. Some PCs have a light sensor and can change brightness when the room gets lighter or darker. Turn off the toggle for changing brightness automatically when lighting changes if you want a fixed level. You can still fine-tune the built-in screen with the slider while it’s on.
• Change brightness based on content. Some Windows 11 PCs adjust brightness and contrast to match what’s on the built-in screen, so dark scenes can look dimmer. Microsoft says these changes are normal. The drop-down offers Off, Always and On Battery Only.

Microsoft says content-based brightness saves power, and that people who edit photos or video, where accurate color matters, may want to change it. Setting it to Off stops the shifts, but Microsoft warns that it can shorten battery life. On Battery Only is a fair middle ground: steady brightness at your desk, savings on the go. If battery life is already a worry, see laptop battery draining fast for the other settings that matter.

On an HDR display, Microsoft notes that Windows changes brightness more gradually, to match how the eye perceives it. A slow fade after you move the slider isn’t a fault on those screens. If neither option appears, your PC doesn’t support it, and the cause of changing brightness lies elsewhere, such as the monitor’s own eco mode.

Fix 5: Check the display driver

On a laptop, Windows controls the built-in screen through the graphics driver. If that driver is missing or replaced by a generic one, the brightness control can disappear or stop responding.

1. Right-click Start and select Device Manager.
2. Expand Display adapters.
3. Check the name. You should see your Intel, AMD, NVIDIA or other graphics chip. If you see Microsoft Basic Display Adapter, or a yellow warning icon, the proper driver isn’t working.
4. Right-click the adapter, select Update driver, then Search automatically for updated driver software. If nothing is found, select Search for updated drivers on Windows update.

Microsoft’s brightness page says Night light is unavailable with Basic Display drivers. It doesn’t say the same about the brightness slider, but the basic driver offers few display features, so getting the real driver installed is the sensible first move. That’s our reasoning, not a Microsoft statement.

If Windows Update has nothing, download the driver from your laptop maker’s support page or the graphics chip maker’s site, matching your Windows version, then use Browse my computer for drivers in the same menu. Laptop makers sometimes customize graphics drivers, so their own download is a safe choice. Not sure which chip you have? See how to check what graphics card you have. Our guide on how to update drivers in Windows 11 explains when a manual update is worth it.

Fix 6: Roll back or reinstall the driver

If brightness stopped working right after an update, the new driver is a good place to start. Microsoft’s Device Manager driver guide notes that going back to the previous driver often fixes problems that began after Windows Update. You need an administrator account.

1. In Device Manager, expand Display adapters, right-click your adapter and select Properties.
2. On the Driver tab, select Roll Back Driver. If the button is grayed out, there’s no earlier driver saved.
3. Pick a reason, select Yes and restart if asked.

If there’s nothing to roll back, reinstall instead. Save your work first, because the screen may go blank for a moment and you’ll restart.

1. Right-click the adapter, select Uninstall device, then Uninstall.
2. Restart from Start > Power > Restart.
3. Windows tries to reinstall the driver on startup. If it doesn’t, use the update steps in Fix 5.

Once a rolled-back driver works, Windows Update may offer the newer one again. If it keeps breaking brightness, our guide on stopping Windows 11 from updating your graphics driver shows how to hold it back.

Known issues

As of November 2026, Microsoft’s Windows 11, version 25H2 known issues and notifications page, last updated on November 10, 2026, lists no issue with brightness, the brightness slider, adaptive brightness or display drivers. Every issue listed there is marked resolved.

If the problem began with a monthly update and none of the fixes help, check that page again, since Microsoft adds issues as they’re confirmed, and roll back the display driver in the meantime.

Related guides

• Screen flickering in Windows 11: how to fix it
• How to update drivers in Windows 11 (and when not to)
• How to check what graphics card you have in Windows 11
• Keyboard not working in Windows 11: how to fix it
• Laptop battery draining fast in Windows 11: how to fix it

Official sources

• Microsoft: Change display brightness and color in Windows
• Microsoft: Update drivers through Device Manager in Windows
• Microsoft: Windows 11, version 25H2 known issues and notifications