Expire Emails from Mimecast

Document created by user.oxriBaJeN4 Employee on Sep 11, 2015Last modified by user.oxriBaJeN4 Employee on Jun 29, 2017
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Preservation policies and your Account Retention setting determine how long Mimecast will retain emails in the archive.


Mimecast does, however also provide different methods to expire emails from the archive before the retention period. This is controlled by the administrator, although access for end users to declare emails for expiry is made available if Folder Based Retention has been implemented in your environment.



Retention Adjustments


Retention Adjustments allow administrators to modify the expiry date for emails in the archive. When an email is initially archived, it is stamped with an expiry date based on the preservation policies. Administrators may need to change the amount of time the email is retained in the archive, which can be modified using a retention adjustment. An adjustment can either be used to expire emails immediately, or to increase / reduce the retention period for emails in the archive.

Permissions are required in order to create and approve a Retention Adjustment.

The process is as follows:

  • An eDiscovery Case is created, which contains archive searches for the email data to be expired.
  • An Discovery Officer creates a retention adjustment, based on the eDiscovery case.
  • A second Discovery Officer approves the expiry request.


For security reasons, only users with the Discover Officer administrator role is able to assign these permissions. Once emails are expired, they cannot be retrieved.


See the Cases knowledge article for further information.


Folder Based Retention


Folder Based Retention allows users to effect reasonable data destruction policies from Outlook using Managed Folders, as well as enabling administrators to manage the life cycle of emails in Exchange and in the archive. This requires the deployment of the Mimecast Synchronization Engine in your internal environment.


Folder Based Retention functionality includes:

  • Giving users the ability to select messages for deletion from Outlook and drop them into Mimecast Managed Folders.  These folders are configured in the Mimecast Administration console, and "pushed" into Exchange (and therefore the end users Outlook client) using Mimecast Synchronization Engine
  • Allowing Administrations to manage Exchange Inbox, Sent Items, Junk Mail and Deleted Items remotely, by setting retention policies for each (with an option to include or exclude subfolders within each folder)
  • Allowing Administrators to manage the lifespan of messages on a time-based lifespan, from Exchange to the Mimecast Archive; until they are finally expired from the Archive permanently.


See the Mailbox Storage Management knowledge base article for further information.


Content Definitions


Preservation Policies are used to stamp emails with a certain retention period when being archived . These policies are based on traffic flow, and as with all Mimecast policies allow for granular control. Therefore multiple policies can be configured to apply different retention periods to specific groups/domains or even individual users.


Content Definitions allow Administrators to perform certain actions based on the words, phrases or regular expressions contained in the subject, body, header or even attachment of an email. One available action, should an email trigger a Content Examination Policy, is that the Content and Metadata Preservation period be changed from the existing preservation policies.


See the Configuring a Content Examination Definition knowledge base article for further information.

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