diff --git a/calendar/inc/class.calendar_bo.inc.php b/calendar/inc/class.calendar_bo.inc.php
index f4e4fa6878..c9cc66f916 100644
--- a/calendar/inc/class.calendar_bo.inc.php
+++ b/calendar/inc/class.calendar_bo.inc.php
@@ -337,6 +337,7 @@ class calendar_bo
 		$users = array();
 		foreach($params['users'] as $user)
 		{
+			$user = trim($user);
 			if ($params['ignore_acl'] || $this->check_perms(EGW_ACL_READ|EGW_ACL_READ_FOR_PARTICIPANTS|EGW_ACL_FREEBUSY,0,$user))
 			{
 				if ($user && !in_array($user,$users))	// already added?
diff --git a/calendar/inc/class.calendar_ui.inc.php b/calendar/inc/class.calendar_ui.inc.php
index fbd4c48360..0fb74ffe79 100644
--- a/calendar/inc/class.calendar_ui.inc.php
+++ b/calendar/inc/class.calendar_ui.inc.php
@@ -177,6 +177,7 @@ class calendar_ui
 		$no_access = $no_access_group = array();
 		foreach(explode(',',$this->owner) as $owner)
 		{
+			$owner = trim($owner);
 			if (is_numeric($owner) && $GLOBALS['egw']->accounts->get_type($owner) == 'g')
 			{
 				foreach($GLOBALS['egw']->accounts->member($owner) as $member)