eDiscovery Export (Beta)

Document created by user.oxriBaJeN4 Employee on Nov 4, 2015Last modified by user.LvZSBz7GLX on Mar 9, 2018
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This application is currently in Beta, and requires a beta agreement to be in place between the customer and Mimecast. The Beta program is by invitation only. To register interest, contact your Account Manager.


IMPORTANT UPDATE 9 March 2018: Our engineers are making steady progress incorporating a PST export option into the Administration Console (see previous update below). We are no longer actively developing the beta app and so our ability to respond to new issues will be limited. Please contact your account manager for further details.

IMPORTANT UPDATE 10 November 2017: We are changing our approach to PST Export. After extensive beta testing we have decided to start work to incorporate PST export as an option within the Export functionality of our Administration Console. This should deliver a more streamlined user experience without requiring a standalone Windows client app. In the interim, we will continue to support the current beta service as-is and we will continue to maintain this document during this transition.

The Mimecast eDiscovery Export service retrieves messages associated with an eDiscovery Case or Litigation Hold, and writes these messages into either PST or EDRM format.


This service does not reproduce user folders from mailboxes. It is primarily intended for bulk export of content from across the archive, and not specifically for export of individual mailboxes.


We recommend that large exports (e.g. more than ~100,000 messages or 5 GB) are divided into a series of smaller exports (e.g. by using adjacent date ranges for the underlying searches).


We recommend you use build 195 or later (eDiscoveryExport  Releases prior to build 129 (i.e. any version earlier than LegalHoldExport are now obsolete.  You may see export errors if you continue to use them.  Please contact us if you need a link to the latest version to continue your testing.


How eDiscovery Export Works


To export eDiscovery:

  1. Log in to the Administration Console.
  2. Identify the eDiscovery Case or Litigation Hold to be exported. They may also create new cases for export.
    New Litigation Holds require archive indexing updates to tag each held message before they can be exported. Customers should allow time for this step to complete before attempting an export. eDiscovery cases are search based, and can be exported immediately after creation.
  3. Start the Windows application and authenticate.
  4. Select the case to be exported from a list.
  5. Specify the:
    • Output format (PST or EDRM)
    • Export folder
    • File name
    • A notification email address
  6. The export commences.


The Administrator can review progress in the application. On completion the Administrator will be notified by email, and they can review an output report along with details of any errors.


Incomplete (previously interrupted) exports can be resumed.


Large exports will span multiple PST files of approximately 2 GB each.





This service is only available to Mimecast archive customers.


The beta app only supports domain and cloud authentication methods. We do not currently support Single Sign-On (SSO). If you use Mimecast SSO, you'll need to:

  1. Create a non-SSO standalone Content Administrator account.
  2. Configure the account with:
    • New Application Settings
    • New Authentication Profile, which does not specify ADFS (i.e. domain or cloud credentials).
  3. Create a new account with membership of the Content Officer administrative role.


Administrator Permissions


Administrators using the client must have all of the following permissions to complete an export. You can read more about roles and permissions here.

  • Case – Read
  • Case – Export
  • Search – Content View


Client Environment


  • 32 or 64-bit Windows Vista or above. Windows XP is not supported.
  • 32 bit Microsoft Outlook 2007 or above. Outlook 2003 and 64-bit Outlook versions are not supported.
  • .NET 4.5.2 libraries installed (or later).


How Do I Use the Application


The application is intended for launching from your local host. Only one instance can be run at a time on any single host. A link to download and install the application will be provided via email from Mimecast when you join the beta program.




Following the launch, the application asks the user to authenticate with appropriate credentials. Administrators must have all of the permissions listed in the requirements section before they can proceed beyond authentication. Depending on your account configuration, you may be able to authenticate using either domain or cloud credentials.


If discovery fails then you are recommended to check and confirm any intermediate web proxy services, and to configure application specific proxy settings if required.





Source Selection


Following successful authentication, you will see a dialog populated with all available export sources. These are grouped by Litigation Hold, eDiscovery, and Incomplete (i.e. previously interrupted exports). Use the radio buttons to select the appropriate category, and make a selection from the list on the left. Details of the selection will be displayed on the right:




If the list is empty, you don't currently have any suitable sources available. In this case you should review the articles on Cases and / or Holds as appropriate.

The list of incomplete exports provides the ability to resume export from the point of interruption. The approximate number of messages remaining for export is shown in the dialog for incomplete exports.

The original export source (whether a hold or a discovery case) must still be available for an incomplete export to complete successfully.




First select the desired export format (PST, EDRM v1.2 or EDRM v2.0). The Export Base Directory defaults to the Windows “Documents” folder.


You can also specify the export filename. If the export is larger than the maximum file size for the format, it will span multiple files, each with the same filename and appended with an incrementing number.


On completion the service will send the export report to the email address given. This is particularly useful as exports can take many hours.




Export Progress


Following confirmation of the options, the export will commence and you can track progress (including estimated completion time) in the Progress dialog.


You must remain logged in with the application running until the export completes. Clicking “Stop” will cause the export to terminate gracefully.


If you click "Stop" or experience an interrupted connection, you will be able to resume the export by repeating these steps and selecting the same export from the "Incomplete" list on the "Source" dialog.






We have found some very large messages cannot be successfully written to PST format. In these cases, the export application will write the large messages to the same target folder as standalone EML files.


Known Issues With This Beta

  • This service does not currently support Single Sign On (SSO). Customers must use an account which authenticates with Domain or Cloud credentials with the application.
  • This service does not currently support export of searches which use the proximity operator (~).
  • This service does not currently support the "Include Items on Litigation Hold" option available for searches from the Administration Console. For these use cases, we recommend you create a new Litigation Hold for the export.
  • For complex searches we generally see better results from export of Litigation Holds since this search method is more mature than the method we use when exporting eDiscovery Cases.  As a rough guide in this case: a complex search might be one with more than 3 logical operators (i.e. AND/OR/NOT), especially when used in a search which references multiple addressee domains/mailboxes in the to/from fields.
  • Tip: when creating a Litigation Hold, it can take a few hours for the Hold to be applied.  This is dependent on the number of items to be held and the load on the grid over this period.  We strongly advise waiting 24 hours before exporting a newly-created Hold.