1 files changed, 1 insertions, 1 deletions

diff --git a/src/libs/dutil/WixToolset.DUtil/inc/deputil.h b/src/libs/dutil/WixToolset.DUtil/inc/deputil.h
index bfe235f3..96f353f6 100644
--- a/src/libs/dutil/WixToolset.DUtil/inc/deputil.h
+++ b/src/libs/dutil/WixToolset.DUtil/inc/deputil.h
@@ -56,7 +56,7 @@ DAPI_(HRESULT) DepCheckDependents(
     __in HKEY hkHive,
     __in_z LPCWSTR wzProviderKey,
     __reserved int iAttributes,
-    __in C_STRINGDICT_HANDLE sdIgnoredDependents,
+    __in_opt C_STRINGDICT_HANDLE sdIgnoredDependents,
     __deref_inout_ecount_opt(*pcDependents) DEPENDENCY** prgDependents,
     __inout LPUINT pcDependents
     );