Double-click on the Prevent changing desktop background setting on your right-hand side. If it is set to Enabled, choose the Not Configured option and click the OK button.

Features Tips & Tricks How to Change the Wallpaper and Other Personalization Settings on Windows 10 Non-Activated By Mark Turner October 30, 2018 ...

Double-click "Personalization," right-click "Prevent changing desktop background" and click "Edit." Click the "Enabled" radio button. Click "OK" to save the change and restart the computer.

Relatively simple ways to remove Windows 7's floating-color-balls start-screen animation, and supply your own background images for the operating system's log-on screen and desktop.