diff -rup ./fb_user.module ./fb_user.module
--- ./fb_user.module	2011-03-22 11:55:18.000000000 -0700
+++ ./fb_user.module	2011-04-05 11:16:47.000000000 -0700
@@ -665,16 +665,18 @@ function fb_user_user_view($account, $vi
  * User is about to be updated.
  */
 function fb_user_user_update(&$edit, $account, $category) {
-  if ($edit['map']) {
-    _fb_user_set_map($account, $edit['map']);
-  }
-  else {
-    // Delete account mapping, because administrator has unchecked the connect option.
-    $num_deleted = db_delete('fb_user')
-      ->condition('uid', $account->uid)
-      ->execute();
+  if (!empty($edit['name'])) {
+    if (!empty($edit['map'])) {
+      _fb_user_set_map($account, $edit['map']);
+    }
+    else {
+      // Delete account mapping, because administrator has unchecked the connect option.
+      $num_deleted = db_delete('fb_user')
+        ->condition('uid', $account->uid)
+        ->execute();
 
-    fb_invoke(FB_OP_POST_USER_DISCONNECT, array('account' => $account), NULL, 'fb_user');
+      fb_invoke(FB_OP_POST_USER_DISCONNECT, array('account' => $account), NULL, 'fb_user');
+    }
   }
 }
 
Only in .: fb_user_user.patch