You can do it in two ways. Using Group Policy or Registry Editior. The former is much more comfortable, but for both of them, you will need an admin account.
- Editing Registry keys
- Using Group Policy
Disable Blurred Background using Registry Keys
Type regedit in the Run prompt, and hit Enter to open the Registry Editor.
Right click in the right pane, and create a new DWORD (32bit) and name it DisableAcrylicBackgroundOnLogon.
Once it is created, double click on edit the value. Set it to 1 to disable the blur effect o t0 to enable it.
Make sure to reboot the computer for the changes to take effect.
No matter which option you choose to change the background, it stays blur when you click on the login button.
As of now, there is no way to disable this feature from the Personalization section. I am hoping that in future, Microsoft will roll out an option to disable Blurred Background on Login Screen via Settings.
Disable Blurred Background using Group Policy
Type gpedit.msc in the Run prompt, and hit Enter.
In the Group Policy Editor, navigate to:
Computer Configuration\Administrative Templates\System\Logon
Then double click to open Show clear logon background settings
The default is Not configured. To disable, select Disabled
Click OK, and check the Login Screen.
- This policy setting disables the acrylic blur effect on logon background image.
- If you enable this policy, the logon background image shows without blur.
If you disable or do not configure this policy, the logon background image adopts the acrylic blur effect.
If it doesn’t work, reboot your computer or check the next time you restart the computer.