diff --git a/src/Dev/DevelopmentAdmin.php b/src/Dev/DevelopmentAdmin.php
index 7d72a49bc..8ee9c371d 100644
--- a/src/Dev/DevelopmentAdmin.php
+++ b/src/Dev/DevelopmentAdmin.php
@@ -57,7 +57,7 @@ class DevelopmentAdmin extends Controller
      *
      * @var array
      */
-    private static $registered_controllers;
+    private static $registered_controllers = [];
 
     /**
      * Assume that CLI equals admin permissions