Tools for minifilter development and testing

This page lists a few tools that are specifically for developing a file system minifilter. Minifilter driver developers are also encouraged to use other driver development tools available through the Windows Driver Kit (WDK).

Fltmc.exe Command

The Fltmc.exe program is a system-supplied command line utility for common minifilter driver management operations. Developers can use Fltmc.exe to load and unload minifilter drivers, attach or detach minifilter drivers from volumes, and enumerate minifilter drivers, instances, and volumes. In a command prompt with administrator privileges, type fltmc help to see the full list of commands.

Fsutil.exe Command

The Fsutil.exe program is a system-supplied command line utility that performs various operations on files. Developers can type fsutil file layout to pretty-print all the details of a file, such as its attributes, time stamps, streams, and so forth.

!fltkd Debugger Extension

The !fltkd debugger extension is provided in the Windows Debugging tools. Commonly used commands include:

Command Description
!cbd The filter manager equivalent of !irp
!filter Lists detailed information about the specified filter
!filters Lists all attached minifilter drivers
!frames Lists all filter manager frames and attached minifilter drivers
!instance Lists detailed information about the specified instance
!volume Lists detailed information about the specified volume
!volumes Lists all volumes and attached minifilter driver instances

In WinDbg, type ! for a full list of commands.

Filter Verifier

Filter Verifier is an option in Driver Verifier that validates minifilter driver usage of filter manager functions. Filter Verifier is installed with the Filter Manager. Developers are recommended to always develop minifilter drivers with Filter Verifier enabled. You can activate the File System Filter Verification feature using the verifier.exe command on the command line.

For information on how to enable Filter Verifier and what it validates, see File System Filter Verification.