diff --git a/src/proto_alpha/lib_client/injection.ml b/src/proto_alpha/lib_client/injection.ml
index de52b65a6..7c4a4351b 100644
--- a/src/proto_alpha/lib_client/injection.ml
+++ b/src/proto_alpha/lib_client/injection.ml
@@ -320,6 +320,15 @@ let may_patch_limits
   match may_need_patching contents with
   | Some contents ->
       simulate cctxt ~chain ~block ?branch contents >>=? fun (_, _, result) ->
+      begin match detect_script_failure result with
+        | Ok () -> return ()
+        | Error _ ->
+            cctxt#message
+              "@[<v 2>This simulation failed:@,%a@]"
+              Operation_result.pp_operation_result
+              (contents, result.contents) >>= fun () ->
+            return ()
+      end >>=? fun () ->
       let res = pack_contents_list contents result.contents in
       patch_list res
   | None -> return contents
diff --git a/src/proto_alpha/lib_client/operation_result.ml b/src/proto_alpha/lib_client/operation_result.ml
index 9d314c7df..b223c321c 100644
--- a/src/proto_alpha/lib_client/operation_result.ml
+++ b/src/proto_alpha/lib_client/operation_result.ml
@@ -221,14 +221,14 @@ let pp_manager_operation_contents_and_result ppf
           "This revelation was successfully applied"
     | Backtracked (Reveal_result, _) ->
         Format.fprintf ppf
-          "@<v 0>This revelation was BACKTRACKED,@,\
+          "@[<v 0>This revelation was BACKTRACKED, \
            its expected effects were NOT applied.@]" ;
     | Applied Delegation_result ->
         Format.fprintf ppf
           "This delegation was successfully applied"
     | Backtracked (Delegation_result, _) ->
         Format.fprintf ppf
-          "@<v 0>This delegation was BACKTRACKED,@,\
+          "@[<v 0>This delegation was BACKTRACKED, \
            its expected effects were NOT applied.@]" ;
     | Applied (Transaction_result _ as tx) ->
         Format.fprintf ppf
@@ -236,7 +236,7 @@ let pp_manager_operation_contents_and_result ppf
         pp_transaction_result tx
     | Backtracked (Transaction_result _ as tx, _errs) ->
         Format.fprintf ppf
-          "@<v 0>This transaction was BACKTRACKED,@,\
+          "@[<v 0>This transaction was BACKTRACKED, \
            its expected effects (as follow) were NOT applied.@]" ;
         pp_transaction_result tx
     | Applied (Origination_result _ as op) ->
@@ -245,7 +245,7 @@ let pp_manager_operation_contents_and_result ppf
         pp_origination_result op
     | Backtracked (Origination_result _ as op, _errs) ->
         Format.fprintf ppf
-          "@<v 0>This origination was BACKTRACKED,@,\
+          "@[<v 0>This origination was BACKTRACKED, \
            its expected effects (as follow) were NOT applied.@]" ;
         pp_origination_result op in
   Format.fprintf ppf