diff --git a/src/threading/Manager.cc b/src/threading/Manager.cc
index 1b6cb551e2..9e0616f0d2 100644
--- a/src/threading/Manager.cc
+++ b/src/threading/Manager.cc
@@ -82,7 +82,17 @@ double Manager::NextTimestamp(double* network_time)
 		{
 		MsgThread* t = *i;
 
-		if ( (*i)->MightHaveOut() && ! t->Killed() )
+		// We check here if there's something ready to read from the
+		// queue. Normally the queue will tell us that reliably via
+		// MightHaveOut() because we keep sending heartbeats that
+		// will ensure that the method will eventually return true.
+		// However, when running without network source and without
+		// any communication, the timer_manager's time will always
+		// remain at 1.0, which means that heartbeats will never be
+		// triggered. In that case, we make sure to still process our
+		// threads from time to time.
+		if ( ((*i)->MightHaveOut() && ! t->Killed())
+		     || (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..b2b3fdaa03 100644
--- a/src/threading/Queue.h
+++ b/src/threading/Queue.h
@@ -63,11 +63,13 @@ 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. In other words, this method helps to avoid locking the queue
+	 * frequently, but doesn't allow you to forgo it completely.
 	 */
-	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.