diff --git a/src/threading/Manager.cc b/src/threading/Manager.cc
index 1b6cb551e2..3bb8dbff3b 100644
--- a/src/threading/Manager.cc
+++ b/src/threading/Manager.cc
@@ -82,7 +82,11 @@ double Manager::NextTimestamp(double* network_time)
 		{
 		MsgThread* t = *i;
 
-		if ( (*i)->MightHaveOut() && ! t->Killed() )
+		if ( ( (*i)->MightHaveOut() && ! t->Killed() ) // there might be something in the queue
+		     // Workaround: when running without network source, and without any communication,
+		     // timer_manager is always 1. Hence the previous if will never trigger heartbeats
+		     // In this case, we still have to check process our threads from time to time.
+		     || ( timer_mgr->Time() == 1.0 && random() % 10000 == 0 ) ) 
 			return timer_mgr->Time();
 		}
 
diff --git a/src/threading/Queue.h b/src/threading/Queue.h
index c4f2bfab00..5c1ddfd28e 100644
--- a/src/threading/Queue.h
+++ b/src/threading/Queue.h
@@ -63,11 +63,12 @@ public:
 	/**
 	 * Returns true if the next Get() operation might succeed. This
 	 * function may occasionally return a value not indicating the actual
-	 * state, but won't do so very often. Occasionally we also return a
-	 * true unconditionally to avoid a deadlock when both pointers happen
-	 * to be equal even though there's stuff queued.
+	 * state, but won't do so very often. Note that this means that it can
+	 * consistently return false even if there is something in the Queue.
+	 * You have to check real queue status from time to time to be sure that
+	 * it is empty.
 	 */
-	bool MaybeReady() { return (read_ptr != write_ptr) || (random() % 10000 == 0); }
+	bool MaybeReady() { return (read_ptr != write_ptr); }
 
 	/** Wake up the reader if it's currently blocked for input. This is
 	 primarily to give it a chance to check termination quickly.