diff --git a/calendar/inc/class.calendar_uiforms.inc.php b/calendar/inc/class.calendar_uiforms.inc.php
index 83ef671bed..cd1e53e55a 100644
--- a/calendar/inc/class.calendar_uiforms.inc.php
+++ b/calendar/inc/class.calendar_uiforms.inc.php
@@ -421,7 +421,7 @@ class calendar_uiforms extends calendar_ui
 								{
 									if(is_numeric($participant))
 									{
-										$uid = 'u'.$participant;
+										$uid = $participant;
 										$id = $participant;
 										$resource = $this->bo->resources[''];
 									}