diff --git a/Include/StrFunc.nsh b/Include/StrFunc.nsh
index 59777335..433118f9 100644
--- a/Include/StrFunc.nsh
+++ b/Include/StrFunc.nsh
@@ -11,8 +11,8 @@ o-----------------------------------------------------------------------------o
 
 !verbose push 3
 !define /IfNDef STRFUNC_VERBOSITY 3
-!define _STRFUNC_VERBOSITY ${STRFUNC_VERBOSITY}
-!define _STRFUNC_CREDITVERBOSITY ${STRFUNC_VERBOSITY}
+!define /IfNDef _STRFUNC_VERBOSITY ${STRFUNC_VERBOSITY}
+!define /IfNDef _STRFUNC_CREDITVERBOSITY ${STRFUNC_VERBOSITY}
 !undef STRFUNC_VERBOSITY
 !verbose ${_STRFUNC_VERBOSITY}