diff --git a/C/threads.c b/C/threads.c
index 8d0174fc4..321b28e16 100755
--- a/C/threads.c
+++ b/C/threads.c
@@ -34,7 +34,7 @@ static char     SccsId[] = "%W% %G%";
 
 #if DEBUG_LOCKS
 
-int debug_locks;
+int debug_locks = TRUE;
 
 static Int p_debug_locks( USES_REGS1 ) { debug_locks = 1; return TRUE; }
 
diff --git a/OPTYap/locks_pthread.h b/OPTYap/locks_pthread.h
index f4d75cd97..f4fa59b6c 100755
--- a/OPTYap/locks_pthread.h
+++ b/OPTYap/locks_pthread.h
@@ -17,7 +17,7 @@
 
 #include <pthread.h>
 
-#define DEBUG_LOCKS 1
+//#define DEBUG_LOCKS 1
 
 #if DEBUG_LOCKS
 int Yap_ThreadID( void );