diff --git a/src/bacnetmstp/bacnetutil.cxx b/src/bacnetmstp/bacnetutil.cxx
index 17d555a4..98dd6de7 100644
--- a/src/bacnetmstp/bacnetutil.cxx
+++ b/src/bacnetmstp/bacnetutil.cxx
@@ -831,6 +831,8 @@ string BACNETUTIL::getAllErrorString()
       return string("UPM Error: ") + getUPMErrorString();
       break;
     }
+
+  return string("Internal Error: Unknown ErrorType");
 }
 
 string BACNETUTIL::getDeviceDescription()