diff --git a/engine/Engine.cpp b/engine/Engine.cpp
index 4271c678..20fd1e9f 100644
--- a/engine/Engine.cpp
+++ b/engine/Engine.cpp
@@ -424,9 +424,13 @@ bool EngineStatusHandler::received(Message &msg)
     msg.retValue() << ",threads=" << Thread::count();
     msg.retValue() << ",workers=" << EnginePrivate::count;
     msg.retValue() << ",mutexes=" << Mutex::count();
-    msg.retValue() << ",locks=" << Mutex::locks();
+    int locks = Mutex::locks();
+    if (locks >= 0)
+	msg.retValue() << ",locks=" << locks;
     msg.retValue() << ",semaphores=" << Semaphore::count();
-    msg.retValue() << ",waiting=" << Semaphore::locks();
+    locks = Semaphore::locks();
+    if (locks >= 0)
+	msg.retValue() << ",waiting=" << locks;
     msg.retValue() << ",acceptcalls=" << lookup(Engine::accept(),Engine::getCallAcceptStates());
     if (msg.getBoolValue("details",true)) {
 	NamedIterator iter(Engine::runParams());
diff --git a/engine/Mutex.cpp b/engine/Mutex.cpp
index 076593ce..0f11ff9b 100644
--- a/engine/Mutex.cpp
+++ b/engine/Mutex.cpp
@@ -611,7 +611,7 @@ int Mutex::count()
 
 int Mutex::locks()
 {
-    return MutexPrivate::s_locks;
+    return s_safety ? MutexPrivate::s_locks : -1;
 }
 
 bool Mutex::efficientTimedLock()
@@ -710,7 +710,7 @@ int Semaphore::count()
 
 int Semaphore::locks()
 {
-    return SemaphorePrivate::s_locks;
+    return s_safety ? SemaphorePrivate::s_locks : -1;
 }
 
 bool Semaphore::efficientTimedLock()
diff --git a/yateclass.h b/yateclass.h
index 06881ecd..4163516e 100644
--- a/yateclass.h
+++ b/yateclass.h
@@ -4514,7 +4514,7 @@ public:
 
     /**
      * Get the number of currently locked mutexes
-     * @return Count of locked mutexes, should be zero at program exit
+     * @return Count of locked mutexes, -1 if unknown (not tracked)
      */
     static int locks();
 
@@ -4649,7 +4649,7 @@ public:
 
     /**
      * Get the number of currently locked (waiting) semaphores
-     * @return Count of locked semaphores, should be zero at program exit
+     * @return Count of locked semaphores, -1 if unknown (not tracked)
      */
     static int locks();