diff --git a/jack/internal.h b/jack/internal.h
index 2a0863e..05800a3 100644
--- a/jack/internal.h
+++ b/jack/internal.h
@@ -61,7 +61,7 @@
 #endif
 
 #ifndef	TRUE
-#define	TRUE	(!FALSE)
+#define	TRUE	(1)
 #endif
 
 typedef struct _jack_engine  jack_engine_t;
@@ -96,8 +96,8 @@ typedef struct {
     int8_t		  new_pos;	/* new position this cycle */
     int8_t		  pending_pos;	/* new position request pending */
     jack_nframes_t	  pending_frame; /* pending frame number */
-    uint32_t		  sync_clients;	/* number of active slowsync clients */
-    uint32_t		  sync_remain;	/* number of them with sync_poll */
+    int32_t		  sync_clients;	/* number of active_slowsync clients */
+    int32_t		  sync_remain;	/* number of them with sync_poll */
     jack_time_t           sync_timeout;
     jack_time_t           sync_time_left;
     jack_frame_timer_t    frame_timer;
@@ -166,14 +166,15 @@ typedef volatile struct {
     volatile jack_client_state_t state;   /* w: engine and client r: engine */
     volatile int8_t     name[JACK_CLIENT_NAME_SIZE+1];
     volatile ClientType type;             /* w: engine r: engine and client */
-    volatile int8_t     active : 1;       /* w: engine r: engine and client */
-    volatile int8_t     dead : 1;         /* r/w: engine */
-    volatile int8_t	timed_out : 1;    /* r/w: engine */
-    volatile int8_t     is_timebase : 1;  /* w: engine, r: engine and client */
-    volatile int8_t     timebase_new : 1; /* w: engine and client, r: engine */
-    volatile int8_t     is_slowsync : 1;  /* w: engine, r: engine and client */
-    volatile int8_t     sync_poll : 1;    /* w: engine and client, r: engine */
-    volatile int8_t     sync_new : 1;     /* w: engine and client, r: engine */
+    volatile int8_t     active;           /* w: engine r: engine and client */
+    volatile int8_t     dead;             /* r/w: engine */
+    volatile int8_t	timed_out;        /* r/w: engine */
+    volatile int8_t     is_timebase;	  /* w: engine, r: engine and client */
+    volatile int8_t     timebase_new;	  /* w: engine and client, r: engine */
+    volatile int8_t     is_slowsync;	  /* w: engine, r: engine and client */
+    volatile int8_t     active_slowsync;  /* w: engine, r: engine and client */
+    volatile int8_t     sync_poll;        /* w: engine and client, r: engine */
+    volatile int8_t     sync_new;         /* w: engine and client, r: engine */
     volatile pid_t      pid;              /* w: client r: engine; client pid */
     volatile pid_t      pgrp;             /* w: client r: engine; client pgrp */
     volatile uint64_t	signalled_at;
diff --git a/jackd/engine.c b/jackd/engine.c
index 3e80e08..44cbe9d 100644
--- a/jackd/engine.c
+++ b/jackd/engine.c
@@ -2590,7 +2590,6 @@ jack_zombify_client (jack_engine_t *engine, jack_client_internal_t *client)
 
 	client->control->dead = TRUE;
 	
-	jack_transport_client_exit (engine, client);
 	jack_client_disconnect (engine, client);
 	jack_client_do_deactivate (engine, client, FALSE);
 }
diff --git a/jackd/transengine.c b/jackd/transengine.c
index a355b1a..78a7de1 100644
--- a/jackd/transengine.c
+++ b/jackd/transengine.c
@@ -59,7 +59,8 @@ jack_sync_poll_new (jack_engine_t *engine, jack_client_internal_t *client)
  *
  *   precondition: caller holds the graph lock. */
 static inline void
-jack_sync_poll_exit (jack_engine_t *engine, jack_client_internal_t *client)
+jack_sync_poll_deactivate (jack_engine_t *engine,
+			   jack_client_internal_t *client)
 {
 	if (client->control->sync_poll) {
 		client->control->sync_poll = 0;
@@ -68,6 +69,9 @@ jack_sync_poll_exit (jack_engine_t *engine, jack_client_internal_t *client)
 		VERBOSE (engine, "sync poll interrupted for client %"
 			 PRIu32 "\n", client->control->id);
 	}
+	client->control->active_slowsync = 0;
+	engine->control->sync_clients--;
+	assert(engine->control->sync_clients >= 0);
 }
 
 /* stop polling all the slow-sync clients
@@ -82,8 +86,7 @@ jack_sync_poll_stop (jack_engine_t *engine)
 	for (node = engine->clients; node; node = jack_slist_next (node)) {
 		jack_client_internal_t *client =
 			(jack_client_internal_t *) node->data;
-		if (client->control->is_slowsync &&
-		    client->control->active &&
+		if (client->control->active_slowsync &&
 		    client->control->sync_poll) {
 			client->control->sync_poll = 0;
 			poll_count++;
@@ -113,8 +116,7 @@ jack_sync_poll_start (jack_engine_t *engine)
 	for (node = engine->clients; node; node = jack_slist_next (node)) {
 		jack_client_internal_t *client =
 			(jack_client_internal_t *) node->data;
-		if (client->control->is_slowsync &&
-		    client->control->active) {
+		if (client->control->active_slowsync) {
 			client->control->sync_poll = 1;
 			sync_count++;
 		}
@@ -248,6 +250,8 @@ void
 jack_transport_activate (jack_engine_t *engine, jack_client_internal_t *client)
 {
 	if (client->control->is_slowsync) {
+		assert(!client->control->active_slowsync);
+		client->control->active_slowsync = 1;
 		engine->control->sync_clients++;
 		jack_sync_poll_new (engine, client);
 	}
@@ -300,8 +304,8 @@ jack_transport_client_exit (jack_engine_t *engine,
 	}
 
 	if (client->control->is_slowsync) {
-		jack_sync_poll_exit(engine, client);
-		engine->control->sync_clients--;
+		if (client->control->active_slowsync)
+			jack_sync_poll_deactivate (engine, client);
 		if (client->control->dead)
 			client->control->is_slowsync = 0;
 	}
@@ -314,6 +318,7 @@ jack_transport_client_new (jack_client_internal_t *client)
 	client->control->is_timebase = 0;
 	client->control->timebase_new = 0;
 	client->control->is_slowsync = 0;
+	client->control->active_slowsync = 0;
 	client->control->sync_poll = 0;
 	client->control->sync_new = 0;
 	client->control->sync_cb = NULL;
@@ -335,10 +340,9 @@ jack_transport_client_reset_sync (jack_engine_t *engine,
 	client = jack_client_internal_by_id (engine, client_id);
 
 	if (client && (client->control->is_slowsync)) {
-		jack_sync_poll_exit(engine, client);
+		if (client->control->active_slowsync)
+			jack_sync_poll_deactivate (engine, client);
 		client->control->is_slowsync = 0;
-		if (client->control->active)
-			engine->control->sync_clients--;
 		ret = 0;
 	}  else
 		ret = EINVAL;
@@ -364,12 +368,14 @@ jack_transport_client_set_sync (jack_engine_t *engine,
 	if (client) {
 		if (!client->control->is_slowsync) {
 			client->control->is_slowsync = 1;
-			if (client->control->active)
+			if (client->control->active) {
+				client->control->active_slowsync = 1;
 				engine->control->sync_clients++;
+			}
 		}
 
 		/* force poll of the new slow-sync client, if active */
-		if (client->control->active)
+		if (client->control->active_slowsync)
 			jack_sync_poll_new (engine, client);
 		ret = 0;
 	}  else
diff --git a/libjack/transclient.c b/libjack/transclient.c
index 6a6f0d1..aa8bb26 100644
--- a/libjack/transclient.c
+++ b/libjack/transclient.c
@@ -145,10 +145,10 @@ jack_call_sync_client (jack_client_t *client)
 	jack_client_control_t *control = client->control;
 	jack_control_t *ectl = client->engine;
 
-	/* Make sure we are still slow-sync; is_slowsync is set in a
-	 * critical section; sync_cb is not. */
+	/* Make sure still active and slow-sync; active_slowsync is
+	 * set in a critical section; sync_cb is not. */
 	if ((ectl->new_pos || control->sync_poll || control->sync_new) &&
-	    control->is_slowsync) {
+	    control->active_slowsync) {
 
 		if (control->sync_cb (ectl->transport_state,
 				      &ectl->current_time,