diff --git a/cmake/winmd_from_idl.cmake b/cmake/winmd_from_idl.cmake
index 9715f55..88ff6f9 100644
--- a/cmake/winmd_from_idl.cmake
+++ b/cmake/winmd_from_idl.cmake
@@ -26,7 +26,7 @@ function(winmd_from_idl)
     endforeach()
     find_platform_package_dir(PACKAGE windows.foundation.foundationcontract PATH_VAR metadata_native WINSDK_VERSION ${winmd_from_idl_WINSDK_VERSION})
     add_custom_command(OUTPUT "${winmd_from_idl_OUT}"
-                       COMMAND ${MIDL} ARGS "${idl_native}" /nologo /winrt /winmd "${winmd_native}" /nomidl /metadata_dir "${metadata_native}" ${midl_args}
+                       COMMAND ${MIDL} ARGS "${idl_native}" /nologo /winrt /winmd "${winmd_native}" /nomidl /h "nul" /metadata_dir "${metadata_native}" ${midl_args}
                        MAIN_DEPENDENCY "${idl_native}"
                        DEPENDS "${idl_native}"
                        )