diff --git a/modules/calendar/e-cal-shell-sidebar.c b/modules/calendar/e-cal-shell-sidebar.c
index be0a3443e2..21c630b549 100644
--- a/modules/calendar/e-cal-shell-sidebar.c
+++ b/modules/calendar/e-cal-shell-sidebar.c
@@ -746,6 +746,7 @@ cal_shell_sidebar_client_removed (ECalShellSidebar *cal_shell_sidebar,
 
 	source = e_cal_get_source (client);
 	uid = e_source_peek_uid (source);
+	g_return_if_fail (uid != NULL);
 
 	g_hash_table_remove (client_table, uid);
 	e_source_selector_unselect_source (selector, source);
diff --git a/modules/calendar/e-memo-shell-sidebar.c b/modules/calendar/e-memo-shell-sidebar.c
index 612b83126b..4c9e2544ba 100644
--- a/modules/calendar/e-memo-shell-sidebar.c
+++ b/modules/calendar/e-memo-shell-sidebar.c
@@ -651,6 +651,7 @@ memo_shell_sidebar_client_removed (EMemoShellSidebar *memo_shell_sidebar,
 
 	source = e_cal_get_source (client);
 	uid = e_source_peek_uid (source);
+	g_return_if_fail (uid != NULL);
 
 	g_hash_table_remove (client_table, uid);
 	e_source_selector_unselect_source (selector, source);
diff --git a/modules/calendar/e-task-shell-sidebar.c b/modules/calendar/e-task-shell-sidebar.c
index c6f6e1526d..99df3b6ab5 100644
--- a/modules/calendar/e-task-shell-sidebar.c
+++ b/modules/calendar/e-task-shell-sidebar.c
@@ -651,6 +651,7 @@ task_shell_sidebar_client_removed (ETaskShellSidebar *task_shell_sidebar,
 
 	source = e_cal_get_source (client);
 	uid = e_source_peek_uid (source);
+	g_return_if_fail (uid != NULL);
 
 	g_hash_table_remove (client_table, uid);
 	e_source_selector_unselect_source (selector, source);