Index: continuum-webapp/src/main/resources/org/apache/maven/continuum/web/action/notifier/MailProjectNotifierEditAction-mailProjectNotifierSave-validation.xml
===================================================================
--- continuum-webapp/src/main/resources/org/apache/maven/continuum/web/action/notifier/MailProjectNotifierEditAction-mailProjectNotifierSave-validation.xml	(revision 618861)
+++ continuum-webapp/src/main/resources/org/apache/maven/continuum/web/action/notifier/MailProjectNotifierEditAction-mailProjectNotifierSave-validation.xml	(working copy)
@@ -23,6 +23,9 @@
 
 <validators>
   <field name="address">
+    <field-validator type="requiredstring">
+      <message key="mailNotifier.address.required"/>
+    </field-validator>
     <field-validator type="email">
       <message key="mailNotifier.address.invalid"/>
     </field-validator>
Index: continuum-webapp/src/main/resources/org/apache/maven/continuum/web/action/notifier/MailGroupNotifierEditAction-mailProjectGroupNotifierSave-validation.xml
===================================================================
--- continuum-webapp/src/main/resources/org/apache/maven/continuum/web/action/notifier/MailGroupNotifierEditAction-mailProjectGroupNotifierSave-validation.xml	(revision 618861)
+++ continuum-webapp/src/main/resources/org/apache/maven/continuum/web/action/notifier/MailGroupNotifierEditAction-mailProjectGroupNotifierSave-validation.xml	(working copy)
@@ -23,6 +23,9 @@
 
 <validators>
   <field name="address">
+    <field-validator type="requiredstring">
+      <message key="mailNotifier.address.required"/>
+    </field-validator>
     <field-validator type="email">
       <message key="mailNotifier.address.invalid"/>
     </field-validator>