diff --git a/libbalsa/mailbox.c b/libbalsa/mailbox.c
index 70deec935..e66d512a8 100644
--- a/libbalsa/mailbox.c
+++ b/libbalsa/mailbox.c
@@ -644,6 +644,8 @@ libbalsa_mailbox_close(LibBalsaMailbox * mailbox, gboolean expunge)
         libbalsa_mailbox_free_mindex(mailbox);
         priv->stamp++;
 	priv->state = LB_MAILBOX_STATE_CLOSED;
+	libbalsa_condition_unref(priv->view_filter);
+	priv->view_filter = NULL;
     }
 
     libbalsa_unlock_mailbox(mailbox);