diff --git a/include/msi.h b/include/msi.h
index e889ace6df4..862bd041335 100644
--- a/include/msi.h
+++ b/include/msi.h
@@ -31,6 +31,7 @@ typedef unsigned long MSIHANDLE;
 
 typedef enum tagINSTALLSTATE
 {
+    INSTALLSTATE_NOTUSED = -7,
     INSTALLSTATE_BADCONFIG = -6,
     INSTALLSTATE_INCOMPLETE = -5,
     INSTALLSTATE_SOURCEABSENT = -4,