diff --git a/webadmin/src/views/users.html b/webadmin/src/views/users.html
index 8212f7ca0..3d0cd6a1c 100644
--- a/webadmin/src/views/users.html
+++ b/webadmin/src/views/users.html
@@ -86,7 +86,7 @@
     <div class="modal-dialog">
         <div class="modal-content">
             <div class="modal-header">
-                <h4 class="modal-title">Edit user {{ useredit.userInfo.username }}</h4>
+                <h4 class="modal-title">Edit user {{ useredit.userInfo.username || useredit.userInfo.email }}</h4>
             </div>
             <div class="modal-body">
                 <form name="useredit_form" role="form" ng-submit="useredit.submit()" autocomplete="off">
diff --git a/webadmin/src/views/users.js b/webadmin/src/views/users.js
index dd53114b3..a84bc7540 100644
--- a/webadmin/src/views/users.js
+++ b/webadmin/src/views/users.js
@@ -177,7 +177,7 @@ angular.module('Application').controller('UsersController', ['$scope', '$locatio
             $scope.useredit.groupIds = angular.copy(userInfo.groupIds);
             $scope.useredit.superuser = userInfo.groupIds.indexOf('admin') !== -1;
 
-            $scope.useredit.availableEmailDomains = $scope.emailDomains.map(function (d) { return { domain: d, address: userInfo.username + '@' + d.domain }; });
+            $scope.useredit.availableEmailDomains = userInfo.username ? $scope.emailDomains.map(function (d) { return { domain: d, address: userInfo.username + '@' + d.domain }; }) : []; // username can be null if invited user has not signed up yet
             $scope.useredit.currentEmailDomains = [];
             $scope.useredit.selectedEmailDomains = [];
             $scope.useredit.aliases = {};