That means you cant see a clear background picture.
The acrylic blur effect is new with Windows 10 version 1903, but not all users like this effect.
You may be interested in this feature.
Click to see more information Do You Want to Know Windows 10 19H1 New Features?
you could Find Here.
However, it will also kill the transparency effect on parameters, Start and other places.
Step 2: Now clickPersonalizationunder the Windows parameters section and clickColorsfrom the left navigation menu.
Step 3: Right-click theSystemfolder, selectNew, selectDWORD (32-bit) Valueand give it the nameDisableAcrylicBackgroundOnLogon.
Finally, clickOKto perform the change.
Step 1: Firstly, typegroup policyin the search bar and clickEdit group policyto enter its interface.
Step 2: Now find the folder:Computer Configuration\Administrative Templates\System\Logonand then click theLogonfolder.
Step 3: Double clickShow clear logon backgroundand checkEnablefrom the pop-up window.
Finally, clickOKto deactivate the blur effect on the Windows 10 login screen.
If you are also bothered by this blur effect, you might try the methods above.
