On Windows 10, you can set an accent color to match your wallpaper, or to contrast with it. You have the choice to let Windows select the right color based on the the wallpaper or you can select one yourself. There are some colors that you simply cannot set as the accent color. They’re too dark or too light. That’s when Windows 10 tells you that the color is not supported. This includes true black however, there’s a registry hack that lets you get true black accent color on Windows 10.
We should mention that this tweak will let you set true black accent color for the title bars, but it may impact text visibility. Some text may no longer be legible so proceed at your own risk. We should also mention that this only changes the color of the title bar as of Windows 10 build 1803. If you’re running an older version, you might get a black taskbar and Start menu. You will need to edit the registry which requires admin rights.
True Black Accent Color
Open the Settings app and go to the Personalization group of settings. Select the Color tab. Turn Transparency off, and disable the ‘Show color on Start, taskbar, and action center’. Leave the ‘Title bars’ option enabled.
Open the Windows registry and navigate to the following location.
Here, look for a value called AccentColor. Double-click it and set its value to 171717. Next look for a key value called ColorPrevalence and double-click it and set its value to 1.
That’s all you need to do. As an extra step, you can create a new DWORD (32-bit) Value named AccentColorInactive and set its value to 444444. This will give color to background windows. You should now have truly black title bars. Set a nice, ominous wallpaper to match and you have a fairly good looking desktop.
To undo this, set the value of the ColorPrevalence value back to 0. Open the Settings app and select a different accent color. Enable transparency effects again if you want, and enable colors for the Start menu, taskbar, and action center.
If for some reason, the change doesn’t take effect right away, restart your system. If you still don’t see the changes reverted, go back to the Windows registry and check the value of the keys that you edited. Revert them back to their original state manually. If all else fails, simply open the Settings app and go to the Personalization group of settings. Select the Theme tab, and enable any theme.