End User Applications: Configuring Delegate Mailbox Access

Document created by user.oxriBaJeN4 Employee on Sep 14, 2015Last modified by user.oxriBaJeN4 Employee on Apr 2, 2019
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This guide describes how to configure delegate mailboxes to provide end users with access to multiple email archives. For example:

  • A user gets married and their email address changes when their name changes. Once a delegate mailbox has been configured, the end user would be able to search for all the messages associated with their new and old account.
  • If using a generic address (e. g. info@domain.com) users can have this generic address added as a delegate mailbox. They are able to view emails that are not emailed for / to themselves.


Users can access delegated mailboxes from Mimecast's end user applications. Delegate mailbox access doesn't include messages that haven't yet been archived (e.g. accepted emails).

You must have Full Administrator, or Super Administrator access to delegate permission to mailboxes. See the Understanding Administrator Roles page for more information.


When adding delegate mailboxes, the following terminology is used: 

  • Primary Address: This is the email address of the primary user who wants delegate access to another user's (the delegate's) mailbox, in addition to their own mailbox.
  • Delegate Address: This is the email address of the user, whose mailbox the primary address user will have delegate access to.

Delegate mailbox configuration will appear in the Administration Console as below:Delegate Mailbox

This is then viewed in Mimecast end user applications as below:

Delegate Mailbox


Excluded Messages


End users are able to change message sensitivity levels to email in Microsoft Outlook. If the sensitivity is changed from the normal status (i.e. to personal or private) and the message is submitted to Mimecast, the Sender Privacy Policy applies. This policy doesn't display in the Administration Console, and is enabled by default for all messages. You can verify if this policy has been applied using the Email Receipt / Delivery View.


If this policy has been applied to a message, the following occurs:

  • The message is not displayed in delegate mailboxes.
  • The policy is not applied retrospectively. It only takes effect when the message is sent through Mimecast (or uploaded through journaling or ingestion).
  • The message isn't replicated to Mimecast through mailbox folder replication.
  • The message is still accessible to the original user in their mailbox archive search, and to administrators through the administration console archive search, or eDiscovery Cases.


Manually Adding Delegate Mailboxes

Multiple delegate mailboxes can be added by repeating the steps listed below for individual addresses, or by following the instructions in the "Importing Delegate Mailbox Access" section below.

To add a delegate mailbox:

  1. Log on to the Administration Console.
  2. Click on the Administration toolbar button. A menu drop down is displayed.
  3. Click on the Directories | Internal Directories menu item.
  4. Click on the Internal Domain of the primary address.
  5. Click on the Domain of the primary address. The domain's email addresses are listed.
  6. Click on the Email Address of the primary address. This displays the Address Settings.
  7. Click on the Add Delegate Mailboxes button from the top toolbar. Any current delegates for the primary address are listed.

    Add Delegate Mailboxes
  8. Click on the Add Delegate Mailbox button to select the delegate mailbox address.

    Delegate Mailbox Address
  9. Click the Lookup button to the right of the "Delegate Mailbox" field.
  10. Type the Name or Email Address of the delegated address in the Search field.
  11. Click on the Search button.
  12. Select the Email Address from the list of results.
  13. Click on the Save and Exit button.


Importing Delegate Mailbox Access


You can import access settings for delegate mailboxes by either using:


If using a formatted spreadsheet, the file's layout is critical for data to import correctly. For guidelines on the spreadsheet import format, read the Importing Users via a Spreadsheet page.


In the example shown,Import_Spreadsheet_Delegate_Mailboxes.png two primary addresses (user1@company.com, user2@company.com) and three delegate addresses are defined. Two delegate addresses have been assigned to the same primary address (i.e. user2@company.com has two delegates of delegate2@company.com and delegate3@company.com).


The key points to note when creating the spreadsheet are:

  1. The spreadsheet must include two key fields for the correct configuration, namely "primaryaddress" and "delegateaddress".
  2. Both the primary address and delegate address must already exist in the internal domains of your account.
  3. You can configure multiple delegates to the same primary address. Each delegate must appear as a separate entry in the spreadsheet (as shown in the example above).
A primary address cannot be a delegate address to itself.

To perform the import, prepare the spreadsheet and associated data before starting the import process. The column headings listed below should be used:

Column HeadingTitleDescriptionExample
primaryaddressEmail AddressThis must be a valid email address, and must not contain spaces, surrounding quotes. etc.user@company.com
delegateaddressNameA valid internal email address (formatted as above) for the delegate mailbox. If you wish to assign more than one delegate to the same primary address, create a separate line in the spreadsheet for each new delegate.delegate1@company.com


  1. Log on to the Administration Console
  2. Click on the Administration toolbar button. A menu drop down is displayed.
  3. Click on the Directories | Internal Directories menu item.
  4. Select the Internal Domain of the primary address.
    The import can be performed for one primary domain at a time.
  5. Select Import Delegate Mailboxes button from the toolbar.
  6. Click on the Choose File button to select the required spreadsheet file.
  7. Click on the Preview Changes button on the toolbar to validate the entries in the Excel file. The results are displayed.
    Preview Delegate Mailboxes
  8. If there are no errors, click on the Accept Import button to start the import process.


The import may take several minutes to complete, depending on the volume of data being imported. Once the import has completed, the delegate address will be added to the Delegate Mailbox listing for the primary address.


Manually Removing Delegate Mailboxes


To remove a delegated mailbox:

  1. Log on to the Administration Console
  2. Click on the Administration toolbar button. A menu drop down is displayed.
  3. Click on the Directories | Internal Directories menu item.
  4. Select the Internal Domain.
  5. Select the User whose delegate mailboxes you want to remove.
  6. Click on the Add Delegate Mailbox button on the toolbar.
  7. Right click on the delegate mailbox to be removed.
  8. Click on the Delete Delegate Mailbox menu item from the popup menu.


Log Files


Following a successful import, the delegate and primary account details can be viewed: 

  1. Log on to the Administration Console
  2. Click on the Administration toolbar menu item.  A menu drop down is displayed.
  3. Click on the Account | Audit Logs menu item. 
    Delegate Mailbox Logs

This information is also sent via email notification to the super and full administrators.


See Also...


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