diff --git a/nodeaccess.module b/nodeaccess.module
index 1b33402..309fda0 100644
--- a/nodeaccess.module
+++ b/nodeaccess.module
@@ -965,9 +965,11 @@ function nodeaccess_delete_user_reference($node) {
   $fields = variable_get('nodeaccess_' . $node->type . '_user_reference', array());
   foreach ($fields as $field_name => $field) {
     $user_uids = field_get_items('node', $node, $field_name);
-    $user_references = user_load_multiple($user_uids);
-    foreach ($user_references as $user) {
-      unset($form_values['uid'][$user->uid]);
+    if ($user_uids) {
+      $user_references = user_load_multiple($user_uids);
+      foreach ($user_references as $user) {
+        unset($form_values['uid'][$user->uid]);
+      }
     }
   }
   $form_values['nid'] = $node->nid;