There have been reports about Exchange 2013 CU14 where Content Indexing failed. I’ve heard about CI failing for some Mailbox databases, Mailbox databases containing Public Folder Mailboxes, but also reports about Exchange 2013 Cu14 servers where CI fails for all Mailbox databases.

In the Event Viewer you can find error messages like:

Watson report about to be sent for process id: 28160, with parameters: E12IIS, c-RTL-AMD64, 15.00.1236.003, M.E.Search.Service, M.E.Data.Directory, M.E.D.D.ScopeSet.GetOrgWideDefaultScopeSet, System.ArgumentNullException, 301, 15.00.1236.000.
ErrorReportingEnabled: False

You can find an extended thread on the Microsoft forums as well: Exchnage 2013 CU 14 Database Indexing failed.

The issue is confirmed by Microsoft and Microsoft is working on a fix for this. At this moment it is unknown whether Microsoft will release an Interim Update (IU) or that it will be made available in CU15.

For now my recommendation would be to NOT INSTALL EXCHANGE 2013 CU14 at all.

Update October 27. If you unfortunately run into this issue after installing Exchange 2013 CU14 there’s no other solution then to install Exchange 2013 CU13 and move all your Mailboxes to this server. I cannot call this a fix or workaround, it’s an ugly fallback scenario.

ps. I’ve heard rumors that this issue also appears in Exchange 2016 CU3 but I cannot confirm if this is the case. If you are planning to deploy Exchange 2016 CU3 I would recommend to thoroughly test CU3 before putting it into production.