diff --git a/phpgwapi/inc/class.preferences.inc.php b/phpgwapi/inc/class.preferences.inc.php
index a790b7d4ba..5dbc1eaee6 100644
--- a/phpgwapi/inc/class.preferences.inc.php
+++ b/phpgwapi/inc/class.preferences.inc.php
@@ -370,6 +370,10 @@
 					{
 						$this->session[$app_name][$var] = $this->data[$app_name][$var] = $value;
 						$GLOBALS['egw']->session->appsession('preferences','preferences',$this->session);
+						if (method_exists($GLOBALS['egw'],'invalidate_session_cache'))	// egw object in setup is limited
+						{
+							$GLOBALS['egw']->invalidate_session_cache();	// in case with cache the egw_info array in the session
+						}
 					}
 					break;