diff --git a/ocaml/xapi/storage_smapiv1_wrapper.ml b/ocaml/xapi/storage_smapiv1_wrapper.ml
index d8cdd75c54..6ac8cfb551 100644
--- a/ocaml/xapi/storage_smapiv1_wrapper.ml
+++ b/ocaml/xapi/storage_smapiv1_wrapper.ml
@@ -1195,7 +1195,7 @@ functor
                 (Storage_interface.Storage_error
                    (Backend_error
                       ( Api_errors.internal_error
-                      , [Printf.sprintf "No tapdisk attach info found"]
+                      , ["No tapdisk attach info found"]
                       )
                    )
                 )