Index: uspace/app/taskdump/taskdump.c
===================================================================
--- uspace/app/taskdump/taskdump.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/app/taskdump/taskdump.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -126,21 +126,22 @@
 static errno_t connect_task(task_id_t task_id)
 {
-	async_sess_t *ksess = async_connect_kbox(task_id);
+	errno_t rc;
+	async_sess_t *ksess = async_connect_kbox(task_id, &rc);
 
 	if (!ksess) {
-		if (errno == ENOTSUP) {
+		if (rc == ENOTSUP) {
 			printf("You do not have userspace debugging support "
 			    "compiled in the kernel.\n");
 			printf("Compile kernel with 'Support for userspace debuggers' "
 			    "(CONFIG_UDEBUG) enabled.\n");
-			return errno;
+			return rc;
 		}
 
 		printf("Error connecting\n");
 		printf("async_connect_kbox(%" PRIu64 ") -> %s", task_id, str_error_name(errno));
-		return errno;
-	}
-
-	errno_t rc = udebug_begin(ksess);
+		return rc;
+	}
+
+	rc = udebug_begin(ksess);
 	if (rc != EOK) {
 		printf("udebug_begin() -> %s\n", str_error_name(rc));
Index: uspace/app/tester/mm/pager1.c
===================================================================
--- uspace/app/tester/mm/pager1.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/app/tester/mm/pager1.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -65,5 +65,6 @@
 	TPRINTF("Connecting to VFS pager...\n");
 
-	vfs_pager_sess = service_connect_blocking(SERVICE_VFS, INTERFACE_PAGER, 0);
+	vfs_pager_sess = service_connect_blocking(SERVICE_VFS, INTERFACE_PAGER,
+	    0, NULL);
 
 	if (!vfs_pager_sess) {
Index: uspace/app/trace/trace.c
===================================================================
--- uspace/app/trace/trace.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/app/trace/trace.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -139,9 +139,8 @@
 
 	if (sess == NULL) {
-		sess = async_connect_kbox(task_id);
+		sess = async_connect_kbox(task_id, &rc);
 		if (sess == NULL) {
 			printf("Error connecting to task %" PRIu64 ".\n",
 			    task_id);
-			rc = EIO;
 			goto error;
 		}
Index: uspace/lib/c/generic/async/client.c
===================================================================
--- uspace/lib/c/generic/async/client.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/lib/c/generic/async/client.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -889,4 +889,5 @@
  * @param arg2  User defined argument.
  * @param arg3  User defined argument.
+ * @param rc    Placeholder for return code. Unused if NULL.
  *
  * @return New session on success or NULL on error.
@@ -894,8 +895,10 @@
  */
 async_sess_t *async_connect_me_to(async_exch_t *exch, iface_t iface,
-    sysarg_t arg2, sysarg_t arg3)
+    sysarg_t arg2, sysarg_t arg3, errno_t *rc)
 {
 	if (exch == NULL) {
-		errno = ENOENT;
+		if (rc != NULL)
+			*rc = ENOENT;
+
 		return NULL;
 	}
@@ -903,13 +906,17 @@
 	async_sess_t *sess = calloc(1, sizeof(async_sess_t));
 	if (sess == NULL) {
-		errno = ENOMEM;
+		if (rc != NULL)
+			*rc = ENOMEM;
+
 		return NULL;
 	}
 
 	cap_phone_handle_t phone;
-	errno_t rc = async_connect_me_to_internal(exch->phone, iface, arg2,
+	errno_t ret = async_connect_me_to_internal(exch->phone, iface, arg2,
 	    arg3, 0, &phone);
-	if (rc != EOK) {
-		errno = rc;
+	if (ret != EOK) {
+		if (rc != NULL)
+			*rc = ret;
+
 		free(sess);
 		return NULL;
@@ -957,4 +964,5 @@
  * @param arg2  User defined argument.
  * @param arg3  User defined argument.
+ * @param rc    Placeholder for return code. Unused if NULL.
  *
  * @return New session on success or NULL on error.
@@ -962,8 +970,10 @@
  */
 async_sess_t *async_connect_me_to_blocking(async_exch_t *exch, iface_t iface,
-    sysarg_t arg2, sysarg_t arg3)
+    sysarg_t arg2, sysarg_t arg3, errno_t *rc)
 {
 	if (exch == NULL) {
-		errno = ENOENT;
+		if (rc != NULL)
+			*rc = ENOENT;
+
 		return NULL;
 	}
@@ -971,13 +981,17 @@
 	async_sess_t *sess = calloc(1, sizeof(async_sess_t));
 	if (sess == NULL) {
-		errno = ENOMEM;
+		if (rc != NULL)
+			*rc = ENOMEM;
+
 		return NULL;
 	}
 
 	cap_phone_handle_t phone;
-	errno_t rc = async_connect_me_to_internal(exch->phone, iface, arg2,
+	errno_t ret = async_connect_me_to_internal(exch->phone, iface, arg2,
 	    arg3, IPC_FLAG_BLOCKING, &phone);
-	if (rc != EOK) {
-		errno = rc;
+	if (ret != EOK) {
+		if (rc != NULL)
+			*rc = ret;
+
 		free(sess);
 		return NULL;
@@ -999,17 +1013,26 @@
 /** Connect to a task specified by id.
  *
- */
-async_sess_t *async_connect_kbox(task_id_t id)
+ * @param id Task to which to connect.
+ * @param rc Placeholder for return code. Unused if NULL.
+ *
+ * @return New session on success or NULL on error.
+ *
+ */
+async_sess_t *async_connect_kbox(task_id_t id, errno_t *rc)
 {
 	async_sess_t *sess = calloc(1, sizeof(async_sess_t));
 	if (sess == NULL) {
-		errno = ENOMEM;
+		if (rc != NULL)
+			*rc = ENOMEM;
+
 		return NULL;
 	}
 
 	cap_phone_handle_t phone;
-	errno_t rc = ipc_connect_kbox(id, &phone);
-	if (rc != EOK) {
-		errno = rc;
+	errno_t ret = ipc_connect_kbox(id, &phone);
+	if (ret != EOK) {
+		if (rc != NULL)
+			*rc = ret;
+
 		free(sess);
 		return NULL;
Index: uspace/lib/c/generic/devman.c
===================================================================
--- uspace/lib/c/generic/devman.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/lib/c/generic/devman.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -89,5 +89,5 @@
 				devman_driver_block_sess =
 				    service_connect_blocking(SERVICE_DEVMAN,
-				    INTERFACE_DDF_DRIVER, 0);
+				    INTERFACE_DDF_DRIVER, 0, NULL);
 		}
 
@@ -108,5 +108,5 @@
 				devman_client_block_sess =
 				    service_connect_blocking(SERVICE_DEVMAN,
-				    INTERFACE_DDF_CLIENT, 0);
+				    INTERFACE_DDF_CLIENT, 0, NULL);
 		}
 
@@ -138,5 +138,5 @@
 			devman_driver_sess =
 			    service_connect(SERVICE_DEVMAN,
-			    INTERFACE_DDF_DRIVER, 0);
+			    INTERFACE_DDF_DRIVER, 0, NULL);
 
 		fibril_mutex_unlock(&devman_driver_mutex);
@@ -152,5 +152,5 @@
 			devman_client_sess =
 			    service_connect(SERVICE_DEVMAN,
-			    INTERFACE_DDF_CLIENT, 0);
+			    INTERFACE_DDF_CLIENT, 0, NULL);
 
 		fibril_mutex_unlock(&devman_client_mutex);
@@ -292,8 +292,8 @@
 	if (flags & IPC_FLAG_BLOCKING)
 		sess = service_connect_blocking(SERVICE_DEVMAN,
-		    INTERFACE_DEVMAN_DEVICE, handle);
+		    INTERFACE_DEVMAN_DEVICE, handle, NULL);
 	else
 		sess = service_connect(SERVICE_DEVMAN,
-		    INTERFACE_DEVMAN_DEVICE, handle);
+		    INTERFACE_DEVMAN_DEVICE, handle, NULL);
 
 	return sess;
@@ -350,8 +350,8 @@
 	if (flags & IPC_FLAG_BLOCKING)
 		sess = service_connect_blocking(SERVICE_DEVMAN,
-		    INTERFACE_DEVMAN_PARENT, handle);
+		    INTERFACE_DEVMAN_PARENT, handle, NULL);
 	else
-		sess = service_connect_blocking(SERVICE_DEVMAN,
-		    INTERFACE_DEVMAN_PARENT, handle);
+		sess = service_connect(SERVICE_DEVMAN,
+		    INTERFACE_DEVMAN_PARENT, handle, NULL);
 
 	return sess;
Index: uspace/lib/c/generic/io/log.c
===================================================================
--- uspace/lib/c/generic/io/log.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/lib/c/generic/io/log.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -167,9 +167,9 @@
 		return ENOMEM;
 
+	errno_t rc;
 	logger_session = service_connect_blocking(SERVICE_LOGGER,
-	    INTERFACE_LOGGER_WRITER, 0);
-	if (logger_session == NULL) {
-		return ENOMEM;
-	}
+	    INTERFACE_LOGGER_WRITER, 0, &rc);
+	if (logger_session == NULL)
+		return rc;
 
 	default_log_id = log_create(prog_name, LOG_NO_PARENT);
Index: uspace/lib/c/generic/io/logctl.c
===================================================================
--- uspace/lib/c/generic/io/logctl.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/lib/c/generic/io/logctl.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -48,8 +48,9 @@
 
 	if (logger_session == NULL) {
+		errno_t rc;
 		logger_session = service_connect_blocking(SERVICE_LOGGER,
-		    INTERFACE_LOGGER_CONTROL, 0);
+		    INTERFACE_LOGGER_CONTROL, 0, &rc);
 		if (logger_session == NULL)
-			return ENOMEM;
+			return rc;
 	}
 
Index: uspace/lib/c/generic/loader.c
===================================================================
--- uspace/lib/c/generic/loader.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/lib/c/generic/loader.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -46,11 +46,13 @@
 #include "private/loader.h"
 
-/** Connect to a new program loader.
- *
- * Spawns a new program loader task and returns the connection structure.
+/** Spawn a new program loader.
+ *
+ * Spawn a new program loader task. The loader then independetly
+ * connects to the naming service.
  *
  * @param name Symbolic name to set on the newly created task.
  *
  * @return Error code.
+ *
  */
 errno_t loader_spawn(const char *name)
@@ -60,5 +62,12 @@
 }
 
-loader_t *loader_connect(void)
+/** Connect to a program loader.
+ *
+ * @param rc Placeholder for return code. Unused if NULL.
+ *
+ * @return Loader structure.
+ *
+ */
+loader_t *loader_connect(errno_t *rc)
 {
 	loader_t *ldr = malloc(sizeof(loader_t));
@@ -67,5 +76,5 @@
 
 	async_sess_t *sess =
-	    service_connect_blocking(SERVICE_LOADER, INTERFACE_LOADER, 0);
+	    service_connect_blocking(SERVICE_LOADER, INTERFACE_LOADER, 0, rc);
 	if (sess == NULL) {
 		free(ldr);
Index: uspace/lib/c/generic/loc.c
===================================================================
--- uspace/lib/c/generic/loc.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/lib/c/generic/loc.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -153,5 +153,5 @@
 				loc_supp_block_sess =
 				    service_connect_blocking(SERVICE_LOC,
-				    INTERFACE_LOC_SUPPLIER, 0);
+				    INTERFACE_LOC_SUPPLIER, 0, NULL);
 		}
 
@@ -172,5 +172,5 @@
 				loc_cons_block_sess =
 				    service_connect_blocking(SERVICE_LOC,
-				    INTERFACE_LOC_CONSUMER, 0);
+				    INTERFACE_LOC_CONSUMER, 0, NULL);
 		}
 
@@ -202,5 +202,5 @@
 			loc_supplier_sess =
 			    service_connect(SERVICE_LOC,
-			    INTERFACE_LOC_SUPPLIER, 0);
+			    INTERFACE_LOC_SUPPLIER, 0, NULL);
 
 		fibril_mutex_unlock(&loc_supplier_mutex);
@@ -216,5 +216,5 @@
 			loc_consumer_sess =
 			    service_connect(SERVICE_LOC,
-			    INTERFACE_LOC_CONSUMER, 0);
+			    INTERFACE_LOC_CONSUMER, 0, NULL);
 
 		fibril_mutex_unlock(&loc_consumer_mutex);
@@ -567,7 +567,7 @@
 
 	if (flags & IPC_FLAG_BLOCKING)
-		sess = service_connect_blocking(SERVICE_LOC, iface, handle);
+		sess = service_connect_blocking(SERVICE_LOC, iface, handle, NULL);
 	else
-		sess = service_connect(SERVICE_LOC, iface, handle);
+		sess = service_connect(SERVICE_LOC, iface, handle, NULL);
 
 	return sess;
Index: uspace/lib/c/generic/ns.c
===================================================================
--- uspace/lib/c/generic/ns.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/lib/c/generic/ns.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -49,10 +49,11 @@
     async_port_handler_t handler, void *data)
 {
-	async_sess_t *sess = ns_session_get();
-	if (sess == NULL)
-		return EIO;
+	errno_t rc;
+	async_sess_t *sess = ns_session_get(&rc);
+	if (sess == NULL)
+		return rc;
 
 	port_id_t port;
-	errno_t rc = async_create_port(iface, handler, data, &port);
+	rc = async_create_port(iface, handler, data, &port);
 	if (rc != EOK)
 		return rc;
@@ -81,7 +82,8 @@
 	async_set_fallback_port_handler(handler, data);
 
-	async_sess_t *sess = ns_session_get();
-	if (sess == NULL)
-		return EIO;
+	errno_t rc;
+	async_sess_t *sess = ns_session_get(&rc);
+	if (sess == NULL)
+		return rc;
 
 	async_exch_t *exch = async_exchange_begin(sess);
@@ -89,5 +91,5 @@
 	ipc_call_t answer;
 	aid_t req = async_send_1(exch, NS_REGISTER_BROKER, service, &answer);
-	errno_t rc = async_connect_to_me(exch, INTERFACE_ANY, service, 0);
+	rc = async_connect_to_me(exch, INTERFACE_ANY, service, 0);
 
 	async_exchange_end(exch);
@@ -103,7 +105,18 @@
 }
 
-async_sess_t *service_connect(service_t service, iface_t iface, sysarg_t arg3)
-{
-	async_sess_t *sess = ns_session_get();
+/** Connect to a singleton service.
+ *
+ * @param service Singleton service ID.
+ * @param iface   Interface to connect to.
+ * @param arg3    Custom connection argument.
+ * @param rc      Placeholder for return code. Unused if NULL.
+ *
+ * @return New session on success or NULL on error.
+ *
+ */
+async_sess_t *service_connect(service_t service, iface_t iface, sysarg_t arg3,
+    errno_t *rc)
+{
+	async_sess_t *sess = ns_session_get(rc);
 	if (sess == NULL)
 		return NULL;
@@ -114,5 +127,5 @@
 
 	async_sess_t *csess =
-	    async_connect_me_to(exch, iface, service, arg3);
+	    async_connect_me_to(exch, iface, service, arg3, rc);
 	async_exchange_end(exch);
 
@@ -130,8 +143,18 @@
 }
 
+/** Wait and connect to a singleton service.
+ *
+ * @param service Singleton service ID.
+ * @param iface   Interface to connect to.
+ * @param arg3    Custom connection argument.
+ * @param rc      Placeholder for return code. Unused if NULL.
+ *
+ * @return New session on success or NULL on error.
+ *
+ */
 async_sess_t *service_connect_blocking(service_t service, iface_t iface,
-    sysarg_t arg3)
-{
-	async_sess_t *sess = ns_session_get();
+    sysarg_t arg3, errno_t *rc)
+{
+	async_sess_t *sess = ns_session_get(rc);
 	if (sess == NULL)
 		return NULL;
@@ -139,5 +162,5 @@
 	async_exch_t *exch = async_exchange_begin(sess);
 	async_sess_t *csess =
-	    async_connect_me_to_blocking(exch, iface, service, arg3);
+	    async_connect_me_to_blocking(exch, iface, service, arg3, rc);
 	async_exchange_end(exch);
 
@@ -157,30 +180,31 @@
 errno_t ns_ping(void)
 {
-	async_sess_t *sess = ns_session_get();
+	errno_t rc;
+	async_sess_t *sess = ns_session_get(&rc);
+	if (sess == NULL)
+		return rc;
+
+	async_exch_t *exch = async_exchange_begin(sess);
+	rc = async_req_0_0(exch, NS_PING);
+	async_exchange_end(exch);
+
+	return rc;
+}
+
+errno_t ns_intro(task_id_t id)
+{
+	errno_t rc;
+	async_sess_t *sess = ns_session_get(&rc);
 	if (sess == NULL)
 		return EIO;
 
 	async_exch_t *exch = async_exchange_begin(sess);
-	errno_t rc = async_req_0_0(exch, NS_PING);
-	async_exchange_end(exch);
-
-	return rc;
-}
-
-errno_t ns_intro(task_id_t id)
-{
-	async_exch_t *exch;
-	async_sess_t *sess = ns_session_get();
-	if (sess == NULL)
-		return EIO;
-
-	exch = async_exchange_begin(sess);
-	errno_t rc = async_req_2_0(exch, NS_ID_INTRO, LOWER32(id), UPPER32(id));
-	async_exchange_end(exch);
-
-	return rc;
-}
-
-async_sess_t *ns_session_get(void)
+	rc = async_req_2_0(exch, NS_ID_INTRO, LOWER32(id), UPPER32(id));
+	async_exchange_end(exch);
+
+	return rc;
+}
+
+async_sess_t *ns_session_get(errno_t *rc)
 {
 	async_exch_t *exch;
@@ -188,5 +212,5 @@
 	if (sess_ns == NULL) {
 		exch = async_exchange_begin(&session_ns);
-		sess_ns = async_connect_me_to(exch, 0, 0, 0);
+		sess_ns = async_connect_me_to(exch, 0, 0, 0, rc);
 		async_exchange_end(exch);
 		if (sess_ns == NULL)
Index: uspace/lib/c/generic/task.c
===================================================================
--- uspace/lib/c/generic/task.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/lib/c/generic/task.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -181,7 +181,8 @@
 
 	/* Connect to a program loader. */
-	loader_t *ldr = loader_connect();
+	errno_t rc;
+	loader_t *ldr = loader_connect(&rc);
 	if (ldr == NULL)
-		return EREFUSED;
+		return rc;
 
 	bool wait_initialized = false;
@@ -189,5 +190,5 @@
 	/* Get task ID. */
 	task_id_t task_id;
-	errno_t rc = loader_get_task_id(ldr, &task_id);
+	rc = loader_get_task_id(ldr, &task_id);
 	if (rc != EOK)
 		goto error;
@@ -250,8 +251,7 @@
 	/* Start a debug session if requested */
 	if (rsess != NULL) {
-		ksess = async_connect_kbox(task_id);
+		ksess = async_connect_kbox(task_id, &rc);
 		if (ksess == NULL) {
 			/* Most likely debugging support is not compiled in */
-			rc = ENOTSUP;
 			goto error;
 		}
@@ -402,7 +402,8 @@
 errno_t task_setup_wait(task_id_t id, task_wait_t *wait)
 {
-	async_sess_t *sess_ns = ns_session_get();
+	errno_t rc;
+	async_sess_t *sess_ns = ns_session_get(&rc);
 	if (sess_ns == NULL)
-		return EIO;
+		return rc;
 
 	async_exch_t *exch = async_exchange_begin(sess_ns);
@@ -484,10 +485,11 @@
 errno_t task_retval(int val)
 {
-	async_sess_t *sess_ns = ns_session_get();
+	errno_t rc;
+	async_sess_t *sess_ns = ns_session_get(&rc);
 	if (sess_ns == NULL)
-		return EIO;
+		return rc;
 
 	async_exch_t *exch = async_exchange_begin(sess_ns);
-	errno_t rc = (errno_t) async_req_1_0(exch, NS_RETVAL, val);
+	rc = (errno_t) async_req_1_0(exch, NS_RETVAL, val);
 	async_exchange_end(exch);
 
Index: uspace/lib/c/generic/vfs/vfs.c
===================================================================
--- uspace/lib/c/generic/vfs/vfs.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/lib/c/generic/vfs/vfs.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -322,5 +322,5 @@
 	while (vfs_sess == NULL) {
 		vfs_sess = service_connect_blocking(SERVICE_VFS, INTERFACE_VFS,
-		    0);
+		    0, NULL);
 	}
 
Index: uspace/lib/c/include/async.h
===================================================================
--- uspace/lib/c/include/async.h	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/lib/c/include/async.h	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -275,8 +275,8 @@
 
 extern async_sess_t *async_connect_me_to(async_exch_t *, iface_t, sysarg_t,
-    sysarg_t);
+    sysarg_t, errno_t *);
 extern async_sess_t *async_connect_me_to_blocking(async_exch_t *, iface_t,
-    sysarg_t, sysarg_t);
-extern async_sess_t *async_connect_kbox(task_id_t);
+    sysarg_t, sysarg_t, errno_t *);
+extern async_sess_t *async_connect_kbox(task_id_t, errno_t *);
 
 extern errno_t async_connect_to_me(async_exch_t *, iface_t, sysarg_t, sysarg_t);
Index: uspace/lib/c/include/loader/loader.h
===================================================================
--- uspace/lib/c/include/loader/loader.h	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/lib/c/include/loader/loader.h	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -44,5 +44,5 @@
 
 extern errno_t loader_spawn(const char *);
-extern loader_t *loader_connect(void);
+extern loader_t *loader_connect(errno_t *);
 extern errno_t loader_get_task_id(loader_t *, task_id_t *);
 extern errno_t loader_set_cwd(loader_t *);
Index: uspace/lib/c/include/ns.h
===================================================================
--- uspace/lib/c/include/ns.h	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/lib/c/include/ns.h	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -43,10 +43,11 @@
     void *);
 extern errno_t service_register_broker(service_t, async_port_handler_t, void *);
-extern async_sess_t *service_connect(service_t, iface_t, sysarg_t);
-extern async_sess_t *service_connect_blocking(service_t, iface_t, sysarg_t);
+extern async_sess_t *service_connect(service_t, iface_t, sysarg_t, errno_t *);
+extern async_sess_t *service_connect_blocking(service_t, iface_t, sysarg_t,
+    errno_t *);
 
 extern errno_t ns_ping(void);
 extern errno_t ns_intro(task_id_t);
-extern async_sess_t *ns_session_get(void);
+extern async_sess_t *ns_session_get(errno_t *);
 
 #endif
Index: uspace/srv/fs/cdfs/cdfs.c
===================================================================
--- uspace/srv/fs/cdfs/cdfs.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/srv/fs/cdfs/cdfs.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -75,12 +75,13 @@
 	}
 
+	errno_t rc;
 	async_sess_t *vfs_sess = service_connect_blocking(SERVICE_VFS,
-	    INTERFACE_VFS_DRIVER, 0);
+	    INTERFACE_VFS_DRIVER, 0, &rc);
 	if (!vfs_sess) {
-		printf("%s: Unable to connect to VFS\n", NAME);
+		printf("%s: Unable to connect to VFS: %s\n", NAME, str_error(rc));
 		return -1;
 	}
 
-	errno_t rc = fs_register(vfs_sess, &cdfs_vfs_info, &cdfs_ops,
+	rc = fs_register(vfs_sess, &cdfs_vfs_info, &cdfs_ops,
 	    &cdfs_libfs_ops);
 	if (rc != EOK) {
Index: uspace/srv/fs/exfat/exfat.c
===================================================================
--- uspace/srv/fs/exfat/exfat.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/srv/fs/exfat/exfat.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -77,7 +77,7 @@
 
 	async_sess_t *vfs_sess = service_connect_blocking(SERVICE_VFS,
-	    INTERFACE_VFS_DRIVER, 0);
+	    INTERFACE_VFS_DRIVER, 0, &rc);
 	if (!vfs_sess) {
-		printf(NAME ": failed to connect to VFS\n");
+		printf(NAME ": failed to connect to VFS: %s\n", str_error(rc));
 		return -1;
 	}
Index: uspace/srv/fs/ext4fs/ext4fs.c
===================================================================
--- uspace/srv/fs/ext4fs/ext4fs.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/srv/fs/ext4fs/ext4fs.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -43,4 +43,5 @@
 #include <ipc/services.h>
 #include <str.h>
+#include <str_error.h>
 #include "ext4/ops.h"
 #include "../../vfs/vfs.h"
@@ -66,14 +67,16 @@
 	}
 
+	errno_t rc;
 	async_sess_t *vfs_sess = service_connect_blocking(SERVICE_VFS,
-	    INTERFACE_VFS_DRIVER, 0);
+	    INTERFACE_VFS_DRIVER, 0, &rc);
 	if (!vfs_sess) {
-		printf("%s: Failed to connect to VFS\n", NAME);
+		printf("%s: Failed to connect to VFS: %s\n", NAME, str_error(rc));
 		return 2;
 	}
 
-	errno_t rc = ext4_global_init();
+	rc = ext4_global_init();
 	if (rc != EOK) {
-		printf("%s: Global initialization failed\n", NAME);
+		printf("%s: Global initialization failed: %s\n", NAME,
+		    str_error(rc));
 		return rc;
 	}
@@ -82,5 +85,6 @@
 	    &ext4_libfs_ops);
 	if (rc != EOK) {
-		printf("%s: Failed to register file system\n", NAME);
+		printf("%s: Failed to register file system: %s\n", NAME,
+		    str_error(rc));
 		return rc;
 	}
Index: uspace/srv/fs/fat/fat.c
===================================================================
--- uspace/srv/fs/fat/fat.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/srv/fs/fat/fat.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -77,7 +77,7 @@
 
 	async_sess_t *vfs_sess = service_connect_blocking(SERVICE_VFS,
-	    INTERFACE_VFS_DRIVER, 0);
+	    INTERFACE_VFS_DRIVER, 0, &rc);
 	if (!vfs_sess) {
-		printf(NAME ": failed to connect to VFS\n");
+		printf(NAME ": failed to connect to VFS: %s\n", str_error(rc));
 		return -1;
 	}
Index: uspace/srv/fs/locfs/locfs.c
===================================================================
--- uspace/srv/fs/locfs/locfs.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/srv/fs/locfs/locfs.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -78,12 +78,13 @@
 	}
 
+	errno_t rc;
 	async_sess_t *vfs_sess = service_connect_blocking(SERVICE_VFS,
-	    INTERFACE_VFS_DRIVER, 0);
+	    INTERFACE_VFS_DRIVER, 0, &rc);
 	if (!vfs_sess) {
-		printf("%s: Unable to connect to VFS\n", NAME);
+		printf("%s: Unable to connect to VFS: %s\n", NAME, str_error(rc));
 		return -1;
 	}
 
-	errno_t rc = fs_register(vfs_sess, &locfs_vfs_info, &locfs_ops,
+	rc = fs_register(vfs_sess, &locfs_vfs_info, &locfs_ops,
 	    &locfs_libfs_ops);
 	if (rc != EOK) {
Index: uspace/srv/fs/mfs/mfs.c
===================================================================
--- uspace/srv/fs/mfs/mfs.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/srv/fs/mfs/mfs.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -74,8 +74,7 @@
 
 	async_sess_t *vfs_sess = service_connect_blocking(SERVICE_VFS,
-	    INTERFACE_VFS_DRIVER, 0);
-
+	    INTERFACE_VFS_DRIVER, 0, &rc);
 	if (!vfs_sess) {
-		printf(NAME ": failed to connect to VFS\n");
+		printf(NAME ": failed to connect to VFS: %s\n", str_error(rc));
 		rc = errno;
 		goto err;
Index: uspace/srv/fs/tmpfs/tmpfs.c
===================================================================
--- uspace/srv/fs/tmpfs/tmpfs.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/srv/fs/tmpfs/tmpfs.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -80,12 +80,13 @@
 	}
 
+	errno_t rc;
 	async_sess_t *vfs_sess = service_connect_blocking(SERVICE_VFS,
-	    INTERFACE_VFS_DRIVER, 0);
+	    INTERFACE_VFS_DRIVER, 0, &rc);
 	if (!vfs_sess) {
-		printf("%s: Unable to connect to VFS\n", NAME);
+		printf("%s: Unable to connect to VFS: %s\n", NAME, str_error(rc));
 		return -1;
 	}
 
-	errno_t rc = fs_register(vfs_sess, &tmpfs_vfs_info, &tmpfs_ops,
+	rc = fs_register(vfs_sess, &tmpfs_vfs_info, &tmpfs_ops,
 	    &tmpfs_libfs_ops);
 	if (rc != EOK) {
Index: uspace/srv/fs/udf/udf.c
===================================================================
--- uspace/srv/fs/udf/udf.c	(revision f8fb03b94de3bfddf9e237f9148481986b407bcb)
+++ uspace/srv/fs/udf/udf.c	(revision 01900b629bbf57a290cd30c16fdaa744836c4c32)
@@ -73,12 +73,14 @@
 	}
 
+	errno_t rc;
 	async_sess_t *vfs_sess =
-	    service_connect_blocking(SERVICE_VFS, INTERFACE_VFS_DRIVER, 0);
+	    service_connect_blocking(SERVICE_VFS, INTERFACE_VFS_DRIVER, 0, &rc);
 	if (!vfs_sess) {
-		log_msg(LOG_DEFAULT, LVL_FATAL, "Failed to connect to VFS");
+		log_msg(LOG_DEFAULT, LVL_FATAL, "Failed to connect to VFS: %s",
+		    str_error(rc));
 		return 2;
 	}
 
-	errno_t rc = fs_register(vfs_sess, &udf_vfs_info, &udf_ops,
+	rc = fs_register(vfs_sess, &udf_vfs_info, &udf_ops,
 	    &udf_libfs_ops);
 	if (rc != EOK)
