diff --git a/common/utils/T/local_tracer.c b/common/utils/T/local_tracer.c
index df6d350a8b..93a56a9e3d 100644
--- a/common/utils/T/local_tracer.c
+++ b/common/utils/T/local_tracer.c
@@ -183,6 +183,10 @@ again:
       break;
 
     case 2: break;
+    default:
+      printf("%s:%d:%s: unhandled message type %d\n",
+          __FILE__, __LINE__, __FUNCTION__, t);
+      abort();
     }
 
     b = buf;