diff --git a/build/jam/BuildSetup b/build/jam/BuildSetup
index 67ec382f81..b5548a2c48 100644
--- a/build/jam/BuildSetup
+++ b/build/jam/BuildSetup
@@ -1011,3 +1011,4 @@ EnableWerror src kits storage ;
 EnableWerror src kits support ;
 EnableWerror src system kernel ;
 EnableWerror src add-ons kernel file_systems bfs ;
+EnableWerror src add-ons kernel file_systems userlandfs ;