diff --git a/Contrib/Modern UI 2/Localization.nsh b/Contrib/Modern UI 2/Localization.nsh
index eda5a682..46db9f97 100644
--- a/Contrib/Modern UI 2/Localization.nsh	
+++ b/Contrib/Modern UI 2/Localization.nsh	
@@ -66,6 +66,10 @@ Localization
   !verbose push
   !verbose ${MUI_VERBOSE}
 
+  !ifndef MUI_LANGDLL_LANGUAGES
+    !warning "MUI_LANGDLL_DISPLAY should only be used after inserting the MUI_LANGUAGE macro(s)"
+  !endif
+
   !insertmacro MUI_LANGDLL_VARIABLES
 
   !insertmacro MUI_DEFAULT MUI_LANGDLL_WINDOWTITLE "Installer Language"
diff --git a/Contrib/Modern UI/System.nsh b/Contrib/Modern UI/System.nsh
index f5f6fbde..f7cfa6da 100644
--- a/Contrib/Modern UI/System.nsh	
+++ b/Contrib/Modern UI/System.nsh	
@@ -2126,6 +2126,10 @@ Var MUI_TEMP2
   !verbose push
   !verbose ${MUI_VERBOSE}
 
+  !ifndef MUI_LANGDLL_LANGUAGES
+    !warning "MUI_LANGDLL_DISPLAY should only be used after inserting the MUI_LANGUAGE macro(s)"
+  !endif
+
   !insertmacro MUI_DEFAULT MUI_LANGDLL_WINDOWTITLE "Installer Language"
   !insertmacro MUI_DEFAULT MUI_LANGDLL_INFO "Please select a language."