diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index d8bea06..1019270 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -488,7 +488,7 @@ function install_begin_request($class_loader, &$install_state) {
 
     // Do not install over a configured settings.php.
     if (Database::getConnectionInfo()) {
-      //throw new AlreadyInstalledException($container->get('string_translation'));
+      throw new AlreadyInstalledException($container->get('string_translation'));
     }
   }