diff --git a/phpgwapi/inc/class.egw_cache.inc.php b/phpgwapi/inc/class.egw_cache.inc.php
index 153871c146..1ea70273e8 100644
--- a/phpgwapi/inc/class.egw_cache.inc.php
+++ b/phpgwapi/inc/class.egw_cache.inc.php
@@ -562,6 +562,15 @@ class egw_cache
 		return $ret;
 	}
 
+	/**
+	 * Unset instance key, so it get read again and re-read install_id from database
+	 */
+	static public function unset_instance_key()
+	{
+		self::$instance_key = null;
+		$GLOBALS['egw_info']['server']['install_id'] = egw_cache::get_system_config('install_id', false);
+	}
+
 	/**
 	 * Key used for instance specific data
 	 *
diff --git a/setup/inc/class.setup_cmd.inc.php b/setup/inc/class.setup_cmd.inc.php
index f37344c8e8..fac04a45a5 100644
--- a/setup/inc/class.setup_cmd.inc.php
+++ b/setup/inc/class.setup_cmd.inc.php
@@ -145,6 +145,9 @@ abstract class setup_cmd extends admin_cmd
 				$GLOBALS['egw_domain'][$domain]['db_pass'],
 				$GLOBALS['egw_domain'][$domain]['db_type']
 			);
+
+			// change caching to managed instance
+			egw_cache::unset_instance_key();
 		}
 	}
 
@@ -165,6 +168,9 @@ abstract class setup_cmd extends admin_cmd
 				$GLOBALS['egw_info']['server']['db_pass'],
 				$GLOBALS['egw_info']['server']['db_type']
 			);
+			// change caching back to own instance
+			egw_cache::unset_instance_key();
+
 			if (!is_null(self::$egw_accounts_backup))
 			{
 				$GLOBALS['egw']->accounts = self::$egw_accounts_backup;
diff --git a/setup/inc/class.setup_cmd_config.inc.php b/setup/inc/class.setup_cmd_config.inc.php
index b8c1dedbee..e2a1421ae7 100644
--- a/setup/inc/class.setup_cmd_config.inc.php
+++ b/setup/inc/class.setup_cmd_config.inc.php
@@ -86,6 +86,9 @@ class setup_cmd_config extends setup_cmd
 		{
 			if ($save_ea_profile) $this->_save_ea_profile();
 
+			// flush instance cache, so above config get read from database not cache
+			egw_cache::flush();
+
 			$this->restore_db();
 
 			return lang('Configuration changed.');