diff --git a/application/Espo/ORM/Defs/EntityDefs.php b/application/Espo/ORM/Defs/EntityDefs.php
index 4006369c91..324a220f99 100644
--- a/application/Espo/ORM/Defs/EntityDefs.php
+++ b/application/Espo/ORM/Defs/EntityDefs.php
@@ -76,7 +76,7 @@ class EntityDefs
     public function getAttributeNameList(): array
     {
         /** @var string[] */
-        return array_keys($this->data['attributes']);
+        return array_keys($this->data['attributes'] ?? []);
     }
 
     /**