If you have Professional Edition of Windows 10, it is likely that changing of desktop background has been disabled in Group Policy Editor.
Enable Changing Desktop Wallpaper in Group Policy.
Press Windows + R to call out the Run dialogue box. Windows 10 only accepts a single folder containing wallpaper collection. Restart your computer to apply this change and see if you are now able to change Desktop Background.Disable the Option via Local Group Policy Editor If you are using Windows Home Edition, you can disable the option via Registry Editor (you might be interested in Windows 10 Home or Windows 10 Pro). To solve this, go to Settings - Ease Of Access - Other Options - Shows windows Background: Turn On It will fix the problem. If you are using the Professional or Enterprise edition of Windows 10, you can disable the option via Local Group Policy Editor. It is possible that the option that prevents you from changing desktop background is enabled.
Fix 4: Disable the Prevent Changing Desktop Background Option
Set Default Background Wallpaper for Windows 10 Desktop Using Group Policy. If your Windows has not been activated, please activate it and you should be able to change your desktop background successfully. This has to be done from your administrator instance. Step 4: Look through the information on the left side to check if your Windows has been activated.
Step 3: Scroll down the left side of the Update & security window and select the Activation option. Step 2: Select the Update & security option from the Settings window. Step 1: Right-click the Windows icon on the taskbar and then select the Settings option. Follow the tutorial below to check if you have activated Windows 10. Select Picture from the Background drop-down list. They apply the desired wallpaper but desktop doesn’t show it. When they try to change the desktop wallpaper from Desktop Properties, following things happen: Wallpaper list as well as Browse button is disabled.
If you have not activated Windows 10, this likely prevents you from changing your desktop background. How to Change the Desktop Background in Windows 10 Right-click your desktop and choose Personalize. Many times Windows users face a strange problem.
Read More Fix 3: Check If Windows 10 Has Been Activated