FilterUnload function (fltuser.h)

An application that has loaded a supporting minifilter by calling FilterLoad can unload the minifilter by calling the FilterUnload function.


HRESULT FilterUnload(
  [in] LPCWSTR lpFilterName


[in] lpFilterName

Pointer to a null-terminated wide-character string containing the same minifilter name that was passed to FilterLoad. This parameter is required and cannot be NULL or an empty string.

Return value

FilterUnload returns S_OK if successful. Otherwise, it returns an error value.


FilterUnload is the Win32 equivalent of FltUnloadFilter.

FilterUnload searches for a registered minifilter whose service name matches the given lpFilterName and calls that minifilter's FilterUnloadCallback (PFLT_FILTER_UNLOAD_CALLBACK) routine.

If the minifilter did not register a FilterUnloadCallback routine, the call to FilterUnload fails.

Callers of FilterUnload must have SeLoadDriverPrivilege (the LUID of SE_LOAD_DRIVER_PRIVILEGE) to load or unload a minifilter driver. This privilege is named by the SE_LOAD_DRIVER_NAME name constant. (Privileges are described in the Microsoft Windows Software Development Kit (SDK) for Windows 7 and .NET Framework 4.0 documentation.)


Requirement Value
Target Platform Universal
Header fltuser.h (include Fltuser.h)
Library FltLib.lib
DLL FltLib.dll

See also