diff --git a/mopidy/stream/__init__.py b/mopidy/stream/__init__.py
index 08e1a0b7..2cb77365 100644
--- a/mopidy/stream/__init__.py
+++ b/mopidy/stream/__init__.py
@@ -19,7 +19,7 @@ class Extension(ext.Extension):
     def get_config_schema(self):
         schema = super(Extension, self).get_config_schema()
         schema['protocols'] = config.List()
-        schema['metadata_blacklist'] = config.List()
+        schema['metadata_blacklist'] = config.List(optional=True)
         schema['timeout'] = config.Integer(
             minimum=1000, maximum=1000 * 60 * 60)
         return schema