diff --git a/CHANGES.txt b/CHANGES.txt
index 0004577..589c5fa 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -4,6 +4,10 @@ Changelog
 2.0RC1 (unreleased)
 -------------------
 
+- Check if the current user has configured an e-mail address for the email 
+  notification option. This fixes http://dev.plone.org/plone/ticket/11428.
+  [timo]
+  
 - Import Owned from OFS.owner to avoid deprecation warnings.
   [timo]
   
@@ -18,6 +22,7 @@ Changelog
   Plone 4.1.
   [timo]
 
+
 1.0RC1 (unreleased)
 -------------------
 
diff --git a/plone/app/discussion/browser/comments.py b/plone/app/discussion/browser/comments.py
index 0c2a9e4..f7fd9c3 100644
--- a/plone/app/discussion/browser/comments.py
+++ b/plone/app/discussion/browser/comments.py
@@ -106,10 +106,17 @@ class CommentForm(extensible.ExtensibleForm, form.Form):
 
         registry = queryUtility(IRegistry)
         settings = registry.forInterface(IDiscussionSettings, check=False)
-        portal_membership = getToolByName(self.context, 'portal_membership')
+        mtool = getToolByName(self.context, 'portal_membership')
+        member = mtool.getAuthenticatedMember()
+        member_email = member.getProperty('email')
 
-        if not settings.user_notification_enabled or portal_membership.isAnonymousUser():
-            self.widgets['user_notification'].mode = interfaces.HIDDEN_MODE
+        # Hide the user_notification checkbox if user notification is disabled 
+        # or the user is not logged in. Also check if the user has a valid email
+        # address
+        if member_email == '' or \
+           not settings.user_notification_enabled or \
+           mtool.isAnonymousUser():
+                self.widgets['user_notification'].mode = interfaces.HIDDEN_MODE
 
     def updateActions(self):
         super(CommentForm, self).updateActions()