diff -up evolution-data-server-3.10.4/calendar/libedata-cal/e-cal-backend.c.calendar-get-timezone-check evolution-data-server-3.10.4/calendar/libedata-cal/e-cal-backend.c

--- evolution-data-server-3.10.4/calendar/libedata-cal/e-cal-backend.c.calendar-get-timezone-check	2013-12-08 19:43:26.000000000 +0100

+++ evolution-data-server-3.10.4/calendar/libedata-cal/e-cal-backend.c	2014-03-14 10:32:46.109041790 +0100

@@ -3832,7 +3832,7 @@ e_cal_backend_get_timezone_finish (ECalB

 	g_return_val_if_fail (

 		g_simple_async_result_is_valid (

 		result, G_OBJECT (backend),

-		e_cal_backend_get_timezone), FALSE);

+		e_cal_backend_get_timezone), NULL);

 	simple = G_SIMPLE_ASYNC_RESULT (result);

 	async_context = g_simple_async_result_get_op_res_gpointer (simple);

@@ -3840,10 +3840,14 @@ e_cal_backend_get_timezone_finish (ECalB

 	cal_backend_unblock_operations (backend, simple);

 	if (g_simple_async_result_propagate_error (simple, error))

-		return FALSE;

+		return NULL;

 	tzobject = g_queue_pop_head (&async_context->result_queue);

-	g_return_val_if_fail (tzobject != NULL, NULL);

+

+	if (!tzobject)

+		g_set_error_literal (error,

+			E_CAL_CLIENT_ERROR, E_CAL_CLIENT_ERROR_OBJECT_NOT_FOUND,

+			e_client_error_to_string (E_CAL_CLIENT_ERROR_OBJECT_NOT_FOUND));

 	g_warn_if_fail (g_queue_is_empty (&async_context->result_queue));