diff --git a/src/TNL/Communicators/MpiCommunicator.h b/src/TNL/Communicators/MpiCommunicator.h
index 86acf01a8f93b6e04c5d910ad10fcb3f26ee042b..d773d3c5a9893cefe218d8cf8a303acf3507216d 100644
--- a/src/TNL/Communicators/MpiCommunicator.h
+++ b/src/TNL/Communicators/MpiCommunicator.h
@@ -283,7 +283,7 @@ class MpiCommunicator
 #endif
         }
 
-         static void Barrier(CommunicationGroup group)
+         static void Barrier( CommunicationGroup group = AllGroup )
          {
 #ifdef HAVE_MPI
             TNL_ASSERT_TRUE(IsInitialized(), "Fatal Error - MPI communicator is not initialized");