diff --git a/src/Module/Admin/Summary.php b/src/Module/Admin/Summary.php
index 6fea2ac6a..d872f4825 100644
--- a/src/Module/Admin/Summary.php
+++ b/src/Module/Admin/Summary.php
@@ -98,6 +98,10 @@ class Summary extends BaseAdmin
 			$warningtext[] = DI::l10n()->t('The last update failed. Please run "php bin/console.php dbstructure update" from the command line and have a look at the errors that might appear. (Some of the errors are possibly inside the logfile.)');
 		}
 
+		if (empty(DI::config()->get('system', 'url'))) {
+			$warningtext[] = DI::l10n()->t('The system.url entry is missing. This is a low level setting and can lead to unexpected behavior. Please add a valid entry as soon as possible in the config file or per console command!');
+		}
+
 		$last_worker_call = DI::keyValue()->get('last_worker_execution');
 		if (!$last_worker_call) {
 			$warningtext[] = DI::l10n()->t('The worker was never executed. Please check your database structure!');