diff --git a/reactos/base/shell/explorer/utility/utility.h b/reactos/base/shell/explorer/utility/utility.h
index 835594a6d84..10a47154aa1 100644
--- a/reactos/base/shell/explorer/utility/utility.h
+++ b/reactos/base/shell/explorer/utility/utility.h
@@ -29,6 +29,7 @@
 #define WIN32_LEAN_AND_MEAN
 #define WIN32_EXTRA_LEAN
 #include <windows.h>
+#include <undocuser.h>
 
  // Unicode support
 #if defined(UNICODE) && !defined(_UNICODE)