diff --git a/gnuradio-runtime/lib/hier_block2_detail.cc b/gnuradio-runtime/lib/hier_block2_detail.cc
index 823d12bc9d..0d4760ce1b 100644
--- a/gnuradio-runtime/lib/hier_block2_detail.cc
+++ b/gnuradio-runtime/lib/hier_block2_detail.cc
@@ -515,6 +515,7 @@ void hier_block2_detail::disconnect_all()
     recursive_disconnect_all(this->d_owner);
     reset_hier_blocks_parent();
     d_fg->clear();
+    d_fg->msg_clear();
     d_blocks.clear();
 
     int max_inputs = d_owner->input_signature()->max_streams();