By default, Windows 11/10 will display your desktop wallpaper as the login screen background. If you wish to display a solid color as a background for your Windows 10 logon screen, then you will be required to edit the Registry. A Windows 11/10 user can replace the desktop background via Personalization settings. This will change the login screen too. But if you wish to remove the logon screen background and set a solid color, read on.
Set Solid color as Windows Login screen background
Please note, that this involves editing the Windows Registry. Wrongly editing the Registry can cause your computer to stop functioning. If you are uncertain or not completely comfortable editing the Registry, we recommend sticking with the default Windows 10 log-in screen. If not, create a system restore point and move on.
Type regedit in Search and click on the result to open the Registry Editor.
Navigate to the following registry key:
Now on the right side, right-click in the empty space and from the context menu, chose New > DWORD (32-Bit), name it DisableLogonBackgroundImage and give it a value 1.
This will remove the default logon screen image and force Windows 11/10 to take a solid color the accent color from your desktop wallpaper.
If you wish to select your own custom color, open Settings > Personalization > Colors.
In Windows 11, against Accent color, select Manual.
In Windows 10, turn the slider to the Off position for Automatically pick an accent color from my desktop.
Restart your computer and check.
To reverse the changes, you need to simply delete the created DWORD or change its value to 0.
Trust this works for you! It worked for me on my Windows PC.