Retention Adjustments

Document created by user.oxriBaJeN4 Employee on Sep 10, 2015Last modified by user.oxriBaJeN4 Employee on Jun 20, 2018
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When a message is archived, it's retention is calculated according to the Maximum Retention setting in your Account Settings. However, there are situations where you may need to modify the expiry date for emails in your organization's Mimecast Archive, so you can:

  • Remove messages from the corporate archive permanently (known as a purge).
  • Reduce the time that messages are kept in the corporate archive (e.g. personal messages).
  • Increase the time messages are kept in the corporate archive. This is useful for customers on a lesser retention period, who upgrade to a longer Maximum Retention setting.


Important Considerations


  • Retention Adjustments are applied to an eDiscovery case and allow you to change the amount of time messages are retained.
  • The adjustment can be set to either expire emails immediately, or after a certain number of days.
  • Retention Adjustments cannot be used to extend the retention period of emails longer than your Maximum Retention setting.
  • Mimecast uses a single instance storage service, where any email that is subject to a Retention Adjustment is updated or expired in its entirety for all recipients of the message.
  • Once a message is expired, it is not recoverable.

Two Administrators with protected Administration Console role permissions are required to complete the Retention Adjustment process; one to create the Retention Adjustment, and a second to approve it.

What You'll Need


  • Two Mimecast Administrators that are members of a protected Administration Console role.
  • An eDiscovery case containing the emails that you want to adjust the retention of.

See the eDiscovery Cases page for more information



The process of adding a retention adjustment involves:

  1. Creating an adjustment request.
  2. Approving the adjustment request. 


Creating the Retention Adjustment Request


To create a retention adjustment request:

  1. Log on to the Administration Console.
  2. Click on the Administration toolbar button. A menu drop down is displayed.
  3. Click on the Archive | Retention Adjustments menu item.
  4. Click on the New Adjustment Request button. The Retention Adjustment Properties dialog is displayed:
    This is only available if you are a member of a protected Administration Console role.
  5. Enter a Description.
  6. Enter any Notes required. This will assist the second approving Administrator to make the final decision regarding the adjustment.
  7. Select the Adjustment Type:
    1. Reset Message Lifespan (based on sent date) - You can reduce the lifespan of messages as required, by entering the number of days in the Days Retention field.
    2. Message Purge Request (Immediate Removal) - This option allows you to instantly expire messages from the Archive.

      Once a message has been expired, it cannot be retrieved. Additionally, as the purge is immediate, the Days Retention field is not available when this option is selected.

  8. Select the applicable eDiscovery Case by clicking on the Lookup button next to the Discovery Case field.
    Only one eDiscovery Case can be selected for each Retention Adjustment Request, and all of the emails within the eDiscovery Case will be affected. If you use an Eternal data range search for the Retention Adjustment it will include future messages sent or received that match the criteria for the eDiscovery case while the Retention Adjustment job is running. At that point, the task will be marked as completed and the retention of items received afterwards will not be adjusted.
  9. Once the eDiscovery Case has been selected, it will be locked, which means that no further searches can be added to the case.
  10. Click on the Save and Exit button to save the request.


The Retention Adjustment should now be listed on the Archive Retention Adjustments page with a status of Awaiting Approval. For auditing purposes, the Retention Adjustment cannot be removed once it has been saved.


Approving a Retention Adjustment Request


Once the request is successfully completed, a second Administrator needs to approve the Retention Adjustment before it will start processing. This cannot be the same Administrator who created the request. If the Administrator who created the request also attempts to approve it, this alert is presented:




To confirm the retention adjustment request:

  1. Log on to the Administration Console.
  2. Click on the Administration toolbar button. A menu drop down is displayed.
  3. Click on the Archive | Retention Adjustments menu item.
  4. Select the Retention Adjustment in the list that requires approval:

  5. Click Confirm Adjustment Request:

  6. The screen is refreshed to display a Status bar:
  7. The list of Retention Adjustment Requests should now display an Adjustment Pending status.

    This will change to Completed once all emails have been processed successfully.

  8. To view the status or details of any adjustment, select it from this list.


Additionally, the progress of a Retention Adjustment can be viewed in the Administration | Archive | Exports and Updates menu item, by clicking on the Archive Updates button in the top menu bar.


Next Steps


Once the Retention Adjustment Job has completed:

  • If you used the Reset Message Lifespan option, verify that the retention has been updated on a selection of the messages in the affected eDiscovery case. See the Viewing Email Retention Information page for more details.
  • If you chose the Purge option, verify that the messages selected to be purged are no longer discoverable in the Mimecast Archive using Archive search.
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