Microsoft has pulled a security update for Exchange 2013 after problems emerged with the latest patch to the email server software just hours after its release. The critical MS13-061 security update for Exchange Server 2013 broke the message index service, preventing Exchange 2013 email users from searching their mailboxes. 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.