Exchange 2013 ищет не все письма

Если "поломались" индексы:

***The  ResetSearchIndex.ps1 used in Exchange 2010 has been deprecated from Exchange 2013***

There are a few different ways to rebuild a search index in
Exchange 2013.

1. Reseed the Search Catalog from another DAG member.
    If the server is part of a DAG, you can reseed the index (Catalog) by running the Update-MailboxDatabaseCopy
   using the –CatalogOnly switch (http://technet.microsoft.com/en-us/library/dd335201(v=exchg.150).aspx)

Example: Update-MailboxDatabaseCopy -Identity DB1\MBX1  -CatalogOnly

In the example above, the Database name is DB1 and the mailbox server is MBX1.

1. Manual rebuild kickoff
1. Stop the “Microsoft Exchange Search service” as
   well as the “Microsoft Exchange Host Controller.”
2. Delete the Existing CI catalog folder or move it
   to a new location.
3. Start the “Microsoft Exchange Search service” as
   well as the “Microsoft Exchange Host Controller” services.

Источник:  http://blogs.technet.com/b/exchangesearch/archive/2013/10/28/rebuild-an-index-on-exchange-2013-for-specific-databases.aspx