diff --git a/inc/drivers_ldap.php b/inc/drivers_ldap.php
index 82ef6af0..017537ea 100644
--- a/inc/drivers_ldap.php
+++ b/inc/drivers_ldap.php
@@ -627,16 +627,19 @@ function sync_LDAP_groups(){
 
       foreach ( $mapping as $field => $value ) {
         dbg_error_log( "LDAP", "Considering copying %s", $field );
-        if ( isset($validUserFields[$field]) ) {
+        if ( isset($validUserFields[$field]) && isset($ldap_values[$value]) ) {
           $user->{$field} = $ldap_values[$value];
           dbg_error_log( "LDAP", "Setting usr->%s to %s from LDAP field %s", $field, $ldap_values[$value], $value );
         }
       }
 
-      if ($user->fullname == "") {
+      // A sane default for the fullname is the group name.
+      if (! isset($user->fullname) || $user->fullname == "") {
         $user->fullname = $group;
       }
 
+      // A sane default for the displayname is the fullname (which might be
+      // the group name).
       if (! isset($user->displayname) || $user->displayname == "") {
         $user->displayname = $user->fullname;
       }