Windows Defender Antivirus Mini-Filter Driver (WdFilter) Service Defaults in Windows 10

Windows Defender Antivirus On-Access Malware Protection Mini-Filter Driver.

Default Settings

Startup type:Boot
Display name:Windows Defender Antivirus Mini-Filter Driver
Service name:WdFilter
Service type:filesys
Error control:normal
Group:FSFilter Anti-Virus
Path:%SystemRoot%\system32\drivers\WdFilter.sys
Registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WdFilter

Default Behavior

Windows Defender Antivirus Mini-Filter Driver is a file system driver. In Windows 10 it is starting by the operating system Boot Loader as a part of the driver stack for the boot volume. If Windows Defender Antivirus Mini-Filter Driver fails to start, the failure details are being recorded into Event Log. Then Windows 10 will start up and notify the user that the WdFilter service has failed to start due to the error.

Dependencies

Windows Defender Antivirus Mini-Filter Driver cannot be started under any conditions, if the FltMgr service is disabled.

While Windows Defender Antivirus Mini-Filter Driver is stopped, the Windows Defender Network Inspection System Driver service cannot be launched.

Restore Default Startup Configuration for Windows Defender Antivirus Mini-Filter Driver

Before you begin doing this, make sure that all the services on which Windows Defender Antivirus Mini-Filter Driver depends are configured by default and function properly. See the list of dependencies above.

1. Run the Command Prompt as an administrator.

2. Copy the commands below, paste them into the command window and press ENTER:

sc config WdFilter start= boot
sc start WdFilter

3. Close the command window and restart the computer.

The WdFilter service is using the WdFilter.sys file that is located in the %WinDir%\system32\drivers folder. If the file is changed, damaged or deleted, you can restore its original version from Windows 10 installation media.