diff --git a/Contrib/Modern UI/Readme.html b/Contrib/Modern UI/Readme.html
index 21ac5a86..a4e87295 100644
--- a/Contrib/Modern UI/Readme.html	
+++ b/Contrib/Modern UI/Readme.html	
@@ -493,6 +493,11 @@ MUI_CUSTOMFUNCTION_INSTFILES_LEAVE
 MUI_CUSTOMFUNCTION_FINISH_PRE<br>
 MUI_CUSTOMFUNCTION_FINISH_SHOW
 </p>
+</p>
+<p class="text">
+<span class="bold">Installer Abort</span><br>
+MUI_CUSTOMFUNCTION_ABORT
+</p>
 <p class="text">
 <span class="bold">Uninstaller - Confirm Page</span><br>
 MUI_UNCUSTOMFUNCTION_CONFIRM_PRE<br>
diff --git a/Contrib/Modern UI/System.nsh b/Contrib/Modern UI/System.nsh
index 1e934e80..7cc6e721 100644
--- a/Contrib/Modern UI/System.nsh	
+++ b/Contrib/Modern UI/System.nsh	
@@ -1471,6 +1471,9 @@
   !ifdef MUI_ABORTWARNING
     Function .onUserAbort
       !insertmacro MUI_ABORTWARNING
+      !ifdef MUI_CUSTOMFUNCTION_ABORT
+        Call "${MUI_CUSTOMFUNCTION_ABORT}"
+      !endif
     FunctionEnd
   !endif