diff --git a/libs/surfaces/mackie/mackie_control_protocol.cc b/libs/surfaces/mackie/mackie_control_protocol.cc
index f4ad499313..22a1d6e8c9 100644
--- a/libs/surfaces/mackie/mackie_control_protocol.cc
+++ b/libs/surfaces/mackie/mackie_control_protocol.cc
@@ -1751,6 +1751,7 @@ MackieControlProtocol::clear_surfaces ()
 {
 	clear_ports ();
 	Glib::Threads::Mutex::Lock lm (surfaces_lock);
+	_master_surface.reset ();
 	surfaces.clear ();	
 }