diff --git a/libs/ardour/midi_track.cc b/libs/ardour/midi_track.cc
index 9fc2755a16..745fa75688 100644
--- a/libs/ardour/midi_track.cc
+++ b/libs/ardour/midi_track.cc
@@ -80,7 +80,7 @@ MidiTrack::use_new_diskstream ()
 	ds->do_refill_with_alloc ();
 	ds->set_block_size (_session.get_block_size ());
 
-	set_diskstream (boost::dynamic_pointer_cast<MidiDiskstream> (ds));
+	set_diskstream (ds);
 }
 
 void
@@ -150,6 +150,14 @@ MidiTrack::_set_state (const XMLNode& node, int version, bool call_base)
 		}
 	}
 
+	if (version >= 3000) {
+		if ((child = find_named_node (node, X_("Diskstream"))) != 0) {
+			boost::shared_ptr<MidiDiskstream> ds (new MidiDiskstream (_session, *child));
+			ds->do_refill_with_alloc ();
+			set_diskstream (ds);
+		}
+	}
+
 	pending_state = const_cast<XMLNode*> (&node);
 
 	if (_session.state_of_the_state() & Session::Loading) {