diff --git a/src/c/threads/mutex.d b/src/c/threads/mutex.d
index cdd91a1..07b4a5d 100755
--- a/src/c/threads/mutex.d
+++ b/src/c/threads/mutex.d
@@ -23,6 +23,21 @@
  * LOCKS or MUTEX
  */
 
+static char *
+lock_name(cl_object lock)
+{
+	char *name = "NIL";
+	cl_object cl_name = lock->lock.name;
+
+	if (cl_name != ECL_NIL) {
+		cl_name = cl_string(cl_name);
+		name = ecl_base_string_pointer_safe(
+		    si_copy_to_simple_base_string(cl_name));
+	}
+
+	return name;
+}
+
 static void
 FEerror_not_a_lock(cl_object lock)
 {
@@ -103,6 +118,8 @@ mp_lock_count(cl_object lock)
 cl_object
 mp_giveup_lock(cl_object lock)
 {
+	print_lock("Unlocking lock %p (%s)\t", lock, lock,
+		   lock_name(lock));
         /* Must be called with interrupts disabled. */
         cl_env_ptr env = ecl_process_env();
 	cl_object own_process = env->own_process;
@@ -117,11 +134,17 @@ mp_giveup_lock(cl_object lock)
 		if (first == ECL_NIL) {
 			lock->lock.owner = ECL_NIL;
 		} else {
+			print_lock("Transfering lock %p (%s) from %p to %p\t",
+				   lock, lock, lock_name(lock),
+				   own_process, first);
 			lock->lock.counter = 1;
 			lock->lock.owner = first;
 			ecl_wakeup_process(first);
 		}
-	} 
+	} else if (lock->lock.counter < 0) {
+		print_lock("Warning, lock %p (%s) has negative count!\t",
+			   lock, lock, lock_name(lock));
+	}
         ecl_return1(env, ECL_T);
 }
 
@@ -135,16 +158,19 @@ get_lock_inner(cl_env_ptr env, cl_object lock)
 				     (AO_t)ECL_NIL, (AO_t)own_process)) {
 		lock->lock.counter = 1;
 		output = ECL_T;
-		print_lock("acquired %p\t", lock, lock);
+		print_lock("Acquired lock %p (%s)\t", lock, lock,
+			   lock_name(lock));
 	} else if (lock->lock.owner == own_process) {
                 unlikely_if (!lock->lock.recursive) {
 			FEerror_not_a_recursive_lock(lock);
 		}
                 ++lock->lock.counter;
 		output = ECL_T;
+		print_lock("Acquired lock %p (%s) recursively\t", lock, lock,
+			   lock_name(lock));
         } else {
-		print_lock("failed acquiring %p for %d\t", lock, lock,
-			   lock->lock.owner);
+		print_lock("Failed acquiring lock %p (%s) for %d\t", lock, lock,
+			   lock_name(lock), lock->lock.owner);
 		output = ECL_NIL;
 	}
 	ecl_enable_interrupts_env(env);
@@ -171,7 +197,8 @@ own_or_get_lock(cl_env_ptr env, cl_object lock)
 				     (AO_t)ECL_NIL, (AO_t)own_process)) {
 		lock->lock.counter = 1;
 		output = ECL_T;
-		print_lock("acquired %p\t", lock, lock);
+		print_lock("Acquired lock %p (%s)\t", lock, lock,
+			   lock_name(lock));
 	} else if (lock->lock.owner == own_process) {
 		output = ECL_T;
         } else {
@@ -189,6 +216,8 @@ mp_get_lock_wait(cl_object lock)
 		FEerror_not_a_lock(lock);
 	}
 	if (get_lock_inner(env, lock) == ECL_NIL) {
+		print_lock("Waiting on lock %p (%s)\t", lock, lock,
+			   lock_name(lock));
 		ecl_wait_on(env, own_or_get_lock, lock);
 	}
 	@(return ECL_T)
@@ -196,6 +225,8 @@ mp_get_lock_wait(cl_object lock)
 
 @(defun mp::get-lock (lock &optional (wait ECL_T))
 @
+	print_lock("Attempting to lock %p (%s)\t", lock, lock,
+		   lock_name(lock));
 	if (Null(wait))
         	return mp_get_lock_nowait(lock);
         else
diff --git a/src/c/threads/queue.d b/src/c/threads/queue.d
index 7aad83b..b4786ff 100755
--- a/src/c/threads/queue.d
+++ b/src/c/threads/queue.d
@@ -364,7 +364,7 @@ ecl_wakeup_waiters(cl_env_ptr the_env, cl_object q, int flags)
 	ecl_process_yield();
 }
 
-#undef print_lock
+/*#undef print_lock*/
 
 void
 print_lock(char *prefix, cl_object l, ...)
@@ -374,10 +374,11 @@ print_lock(char *prefix, cl_object l, ...)
 	va_start(args, l);
 	if (l == ECL_NIL
 	    || type_of(l) == t_condition_variable
+	    || type_of(l) == t_lock
 	    || ECL_FIXNUMP(l->lock.name)) {
 		cl_env_ptr env = ecl_process_env();
 		ecl_get_spinlock(env, &lock);
-		printf("\n%ld\t", ecl_fixnum(env->own_process->process.name));
+		printf("\n%p\t", env->own_process);
 		vprintf(prefix, args);
 		if (l != ECL_NIL) {
 			cl_object p = l->lock.queue_list;
diff --git a/src/h/internal.h b/src/h/internal.h
index b6d3b97..a9b260d 100755
--- a/src/h/internal.h
+++ b/src/h/internal.h
@@ -489,7 +489,7 @@ extern cl_fixnum ecl_runtime(void);
 #ifdef ECL_THREADS
 extern void ecl_process_yield(void);
 extern void print_lock(char *s, cl_object lock, ...);
-#define print_lock(a,b,...) ((void)0)
+/*#define print_lock(a,b,...) ((void)0)*/
 extern void ecl_get_spinlock(cl_env_ptr env, cl_object *lock);
 extern void ecl_giveup_spinlock(cl_object *lock);
 extern cl_object ecl_wait_on(cl_env_ptr env, cl_object (*condition)(cl_env_ptr, cl_object), cl_object o);