Hi uEFImaster
Go into the Settings App - Personalisation - LockScreen
Set Background to picture and choose one
Then open Windows File Explorer and paste each of these into the Address Bar
Delete everything in each folder
%USERPROFILE%/AppData\Local\Packages\Microsoft.Windows.ContentDeliveryManager_cw5n1h2txyewy\LocalState\Assets
%USERPROFILE%/AppData\Local\Packages\Microsoft.Windows.ContentDeliveryManager_cw5n1h2txyewy\Settings
Then right click your Start Button, choose Powershell (admin)
Run (copy and Paste) this command and hit Enter
Get-AppxPackage -allusers *ContentDeliveryManager* | foreach {Add-AppxPackage "$($_.InstallLocation)\appxmanifest.xml" -DisableDevelopmentMode -register }
Restart (not shut down) your PC
Go into the Settings App - Personalisation - LockScreen
Set Background to Windows Spotlight