Late last night we became aware of an issue with MS13-061 security update for Exchange Server 2013. Specifically, after the installation of the security update, the Content Index for mailbox databases shows as Failed and the Microsoft Exchange Search Host Controller service is renamed.
For those that have already installed the MS13-061 security update for Exchange Server 2013, we already have KB 2879739 that provides the steps on how to resolve this issue. However, due to this issue and that it affects all Mailbox server installations, we have decided to pull the MS13-061 security update temporarily.
Read more at source: http://blogs.technet.com/b/exchange/archive/2013/08/14/exchange-2013-security-update-ms13-061-status-update.aspx