In Microsoft’s latest updated (May 2019), the background on the login screen is blurred by default. Since people generally hate change, and are often trying to find ways to get back to what’s familiar, here’s a quick tutorial on how to remove the blurred background in favor of the typical image you’d expect on the Windows 10 login screen.
1. Click Start.
2. Click the gear icon, to open Settings.
3. In the Settings window, click Personalization.
4. In the right pane, click Colors.
5. In the Colors window, scroll down to find More options.
6. Set the Transparency effects to Off.
7. Click X to close the Settings window.