Applies to: Exchange Server 2013

Topic Last Modified: 2013-02-12

In Microsoft Exchange Server 2013 and Exchange Online, Exchange Search includes filters for indexing most common types of file formats included as message attachments. You can also install filters to index additional file types.

When managing or using Exchange Search and the dependent features (such as In-Place eDiscovery), consider the difference between unsearchable items and file formats that are disabled for indexing or contain content that can’t be indexed:

• Unsearchable items   When Exchange Search can't index a particular file type for any reason (for example, if a filter isn't installed), the search for the file type fails. Messages containing such attachments are marked as partially indexed. Unsearchable items can be retrieved using the Get-FailedContentIndexDocuments cmdlet. When copying In-Place eDiscovery search results to a discovery mailbox, you can include unsearchable items.
  
  

  Note:
  Although a message attachment may be unsearchable, the message subject, message body and other metadata may be indexed and returned in searches.

• File formats with content that can’t be indexed   Certain file types such as Windows Media Video (WMV) don't contain content that can be indexed and therefore aren't indexed. Messages containing attachments of such file types aren’t returned as unsearchable items in In-Place eDiscovery searches.
  
  
• Disabled file formats In on-premises organizations, an administrator can disable indexing of a specified file format. Messages that contain an attachment that is of a disabled format aren’t returned as unsearchable items.
  
  

For additional management tasks related to Exchange Search in on-premises organizations, see Exchange Search Procedures.

Default filters