diff --git a/libs/ardour/globals.cc b/libs/ardour/globals.cc
index aa04c8b091..ba6a7383c8 100644
--- a/libs/ardour/globals.cc
+++ b/libs/ardour/globals.cc
@@ -167,22 +167,22 @@ ARDOUR::setup_midi (AudioEngine& engine)
 		/* If that didn't work, just use the first listed port */
 
 		if (default_mmc_port == 0) {
-			default_mmc_port = MIDI::Manager::instance()->port (0);
+			default_mmc_port = MIDI::Manager::instance()->port ("");
 		}
 
 		if (default_mtc_port == 0) {
-			default_mtc_port = MIDI::Manager::instance()->port (0);
+			default_mtc_port = MIDI::Manager::instance()->port ("");
 		}
 
 		if (default_midi_port == 0) {
-			default_midi_port = MIDI::Manager::instance()->port (0);
+			default_midi_port = MIDI::Manager::instance()->port ("");
 		}
 		
 	} else {
 
 		/* Only one port described, so use it for both MTC and MMC */
 
-		default_mmc_port = MIDI::Manager::instance()->port (0);
+		default_mmc_port = MIDI::Manager::instance()->port ("");
 		default_mtc_port = default_mmc_port;
 		default_midi_port = default_mmc_port;
 	}
diff --git a/libs/ardour/session_midi.cc b/libs/ardour/session_midi.cc
index ba3e6401e6..177b2ef54a 100644
--- a/libs/ardour/session_midi.cc
+++ b/libs/ardour/session_midi.cc
@@ -408,7 +408,7 @@ Session::setup_midi_control ()
 	
 	mmc_buffer[0] = 0xf0; // SysEx
 	mmc_buffer[1] = 0x7f; // Real Time SysEx ID for MMC
-	mmc_buffer[2] = mmc->send_device_id();
+	mmc_buffer[2] = (mmc ? mmc->send_device_id() : 0x00);
 	mmc_buffer[3] = 0x6;  // MCC
 
 	/* Set up the qtr frame message */