diff --git a/Contrib/Modern UI/System.nsh b/Contrib/Modern UI/System.nsh
index 20d372f3..d1b2238b 100644
--- a/Contrib/Modern UI/System.nsh	
+++ b/Contrib/Modern UI/System.nsh	
@@ -1134,6 +1134,12 @@
     !define "MUI_LANGUAGEFILE_${LANGUAGE}_USED"
 
     LoadLanguageFile "${NSISDIR}\Contrib\Language files\${LANGUAGE}.nlf"
+
+  !else
+
+    !error "${LANGUAGE} included twice!"
+
+  !endif
   
 !macroend
 
@@ -1328,8 +1334,6 @@
     !undef MUI_TEXT_CONTINUE_INSTALL
   !endif
   
-  !endif
-  
   !undef MUI_LANGUAGEFILE_CURRENT
   
   !verbose 4