diff --git a/lib/private/connector/sabre/maintenanceplugin.php b/lib/private/connector/sabre/maintenanceplugin.php
index 91c48a45d3fa17a53d82f282812d3a99a96d3124..c4c9a5340bc871fb4a3caf966c6da7e7871eb4c5 100644
--- a/lib/private/connector/sabre/maintenanceplugin.php
+++ b/lib/private/connector/sabre/maintenanceplugin.php
@@ -60,6 +60,9 @@ class MaintenancePlugin extends \Sabre\DAV\ServerPlugin
 	 * @return bool
 	 */
 	public function checkMaintenanceMode() {
+		if (\OC::$server->getSystemConfig()->getValue('singleuser', false)) {
+			throw new \Sabre\DAV\Exception\ServiceUnavailable();
+		}
 		if (\OC_Config::getValue('maintenance', false)) {
 			throw new \Sabre\DAV\Exception\ServiceUnavailable();
 		}