For example, the on-screen image, including the wallpaper, will look very blurry if the monitor supports a 1920 by 1080 resolution, but Windows 8 is configured to output at a 1366 by 768 resolution.

Learn how to enable or disable Blurred Background on Login Screen, also called as Acrylic Blur Effect on Sign-in Screen on your Windows 11/10 computer.

The Alt+Tab in Windows 11 blurs the background. If you want to remove Alt + Tab blur background in Windows 11, this article shows you how to do that.