diff --git a/libs/midi++2/mtc.cc b/libs/midi++2/mtc.cc
index 32fb8cf3d6..d1bb7c9bad 100644
--- a/libs/midi++2/mtc.cc
+++ b/libs/midi++2/mtc.cc
@@ -33,7 +33,7 @@ using namespace std;
 using namespace sigc;
 using namespace MIDI;
 
-#define DEBUG_MTC
+#undef DEBUG_MTC
 
 bool
 Parser::possible_mtc (byte *sysex_buf, size_t msglen)