--- cyrus-imapd-2.5.7/imap/sync_client.c.orig	2016-05-22 00:56:24.302742893 +0000
+++ cyrus-imapd-2.5.7/imap/sync_client.c	2016-05-22 10:25:34.956598506 +0000
@@ -2621,6 +2621,10 @@
 	/* Check for shutdown file */
 	if (sync_shutdown_file && !stat(sync_shutdown_file, &sbuf)) {
 	    unlink(sync_shutdown_file);
+	    /* Have to exit with r == 0 or do_daemon() will call us again.
+	     * The value of r is unknown from calls to sync_log_reader_begin() below.
+	    */
+	    r = 0;
 	    break;
 	}