Windows Defender Mini-Filter Driver (WdFilter) Service Defaults in Windows 8

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

Default Settings

Startup type:Boot
Display name:Windows Defender 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

The Windows Defender Mini-Filter Driver service is a file system driver. In Windows 8 it is being loaded by Boot Loader before Kernel initialization. If Windows Defender Mini-Filter Driver fails to start, the error details are added to Windows 8 error log. When the operating system startup is complete, the user is being notified that the WdFilter service hasn't been started.

Dependencies

Windows Defender Mini-Filter Driver can't start, if the FltMgr service is disabled or not available.

Restore Default Startup Configuration for Windows Defender Mini-Filter Driver

Before you begin doing this, make sure that all the services on which Windows Defender 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 corrupted or deleted, you can put it back in there.