An Office 365 administrator can simplify the task of managing the deleted items by creating archiving and deletion policies. Such policies can perform the automatic action of moving the emails to either the archive mailbox or the Deleted items folder instantly from the mailbox. Such policies are called retention policies, and they trigger the action after a certain period. They are called retention tags. In them, the administrator mentions which item to move, when to move, and where to move. These tags are attached to the specific messages or folder of the user’s mailbox. The tag keeps track of the timeline of the selected, and after the expiry of the timeline, it moves the content to the archive mailbox or deletes it permanently.

The tasks that the administrator need to perform regarding the policy creation are:

  1. Enable the archive mailbox for each user of the organization so that the retention tag will find it easier to move the objects in it. Also, if the user archives any information, then it comes in the archive mailbox. It also increases the mailbox storage.
  2. Create retention tags as per the three criteria:
    • Move the messages from the primary mailbox to the archive mailbox after 3 years. It will give you some free space in the mailbox.
    • Delete the 7-year older messages from the deleted items folder permanently
    • Permanently delete the 7-year older messages from both archive and deleted items folder. Sometimes, the businesses must follow the compliance regulations, but most of the time, 7 years is enough period to delete the messages completely.
  3. Create user-defined retention tags to handle the content. These are custom tags that a user assigns to a specific message of the mailbox.


  1. Enable Users’ Archive Mailboxes
  2. Create new Retention tags for Archive & Deletion
  3. Create a new Retention Policy
  4. Assign new Policy to User Mailboxes

Step 1.Enabling Archive Mailboxes for User

We are going enable the Archive mailboxes for the users. To do this, execute the steps as mentioned in sequence:

  1. Sign in to your Office 365 account with the credentials.
  2. Go to Office 365 Security & Compliance Center, click Data governance>>Archive.
  3. Then select the mailboxes whose Archive mailbox is to be enabled (for multiple mailboxes, select using Ctrl key) and then click Enable on the right side.
  4. It will ask for the confirmation with a warning message like this:
  5. Once the process is completed, click the Refresh button on top. Your mailboxes are archive enabled now.

Step 2. Creating Retention Tags for Archive and Deletion Policies

We are going to create three types of retention tags for the new retention (Archive and Deletion) policy in this step. Let us assign a common name (as per your choice) for these retention tags. Here, we are using Kernel.

  • Kernel 3 year Move to Archive (Custom Archive Policy)
  • Kernel 7 year Permanently Delete (Custom Deletion Policy)
  • Kernel Deleted Items and Allow Recovery 5 years (Custom tag for Deleted items folders)
Kernel 3 year Move to Archive (Custom Archive Policy)

This tag will automatically move items older than 3 years to Archive mailboxes. To create the custom tag, just follow the steps:

  1. In the Office 365 admin center, click Admin Centers>>Exchange.
  2. In the Exchange Admin Center, go to Compliance Management and click Retention Tags. Click the + button and select the first option applied automatically to entire mailbox (default).
  3. On the new tag applied automatically to entire mailbox (default) page, provide the required details like Name, Retention action – Move to Archive, Retention period – 1095 days (3 years) with Comment (optional). Click Save to save the entries.
Kernel 7 year Permanently Delete (Custom Deletion Policy)

This tag will permanently delete items after 7 years. To create a custom retention tag, perform the steps:

  1. In Exchange Admin Center>>Compliance Management>>Retention Tags, click the + button and select applied automatically to entire mailbox (default).
  2. It will open the page new tag applied automatically to entire mailbox (default). Here, provide Name, select Retention action as Permanently Delete. Enter Retention period as 2555 days (7 years). Then, click Save to save the settings for this Retention tag.
Kernel Deleted Items and Allow Recovery 5 years (Custom tag for Deleted items folders)

This tag will automatically delete folder items after 5 years. It also provides a recovery period in which the user can recover those items with using Recover Deleted Items feature.

  1. On the retention tags page, select applied automatically to a default folder option from the list now.
  2. A page named new tag automatically applied to a default folder will get open. Provide a Name, select Deleted items from the list, select Delete and Allow Recovery as Retention action and enter 1824 days (5 years) as Retention period. Click Save to create this tag.

Step 3.

When you create an account in Office 365, a Default MRM Policy is created. You have to create a new retention policy and replace it with the Default MRM policy. After creating a new retention policy, the user has to assign the created retention tags to it. Let us see how to create the retention policy and add retention tags to it.

  1. Go to Exchange Admin Center>>Compliance Management >> Retention Policies. Click the + button.
  2. In the new retention policy page, enter a Name and then click + (add) button under Retention tags.
  3. In select retention tags, select the three newly created retention tags. Along with them, select the following tags:
    • Junk Email
    • Never Delete
    • 1 Month Delete
    • 1 Year Delete
    • Personal 1 year move to archive
    • Recoverable items 14 days move to archive

    After the selection, click add option to add the tags. Click OK to save the Retention tags.

  4. In the Retention policies page, select your created retention policy and click Save. You can view the tags linked to it within the right pane.
Step 4. Assign new Retention Policy to User Mailboxes

This step requires assigning a new retention policy to the user mailboxes of the Office 365 account. Perform the steps below to do this:

  1. Navigate to Exchange Admin Center, select Recipients and then click Mailboxes. Select the user mailboxes you want to assign the policy and on right side panel, click More options and click Update for Retention Policy.
  2. On the Bulk Assign Retention Policy page, select your created retention policy from the drop-down list and click Save.

Hence the new Retention Policy is assigned to all the selected user mailboxes. To confirm, go to Mailboxes page, select the mailbox, and click Edit and then on Mailbox features option where you can confirm the assigned retention policy.

We have seen how to setup Archive and Deletion Policy for Office 365 mailboxes. It may take 7 days to for new retention policies to be applied to user mailboxes in Office 365. However, you can force this using the cmdlet: Start-ManagedFolderAssistant in Exchange Online PowerShell cmdlet.

To do this, execute the following command.

  1. Open your Windows PowerShell on your local system (run it as administrator).
  2. After opening, run the following command.
  3. $UserCredential = Get-Credential

  4. Then a dialogue box named Windows PowerShell Credential Request gets opened. Type your Office 365 global admin account username and password and then click OK.
  5. Execute the following command:
  6. Session = New-PSSession –ConfigurationName Microsoft.Exchange –ConnectionUri -Credential $UserCredential –Authentication Basic -AllowRedirection

    Then, run this command:

    Import-PSSession $Session

    To verify Exchange Online connection, run this command to get all mailboxes from your specified Office 365 account:


    Now run:

    Get-mailbox -resultsize unlimited

    Finally, run this command to complete the process:

    $Mailboxes.Identity | Start-ManagedFolderAssistant

Users are provided with a detailed manual procedure for assigning Archive and Deletion Policy for Office 365 mailboxes. It may take 7 days for the policy to come into effect. However, you can implement it forcefully (by starting Managed Folder Assistant using Windows PowerShell cmdlets) to apply retention policy immediately to the Office 365 mailboxes.

KernelOffice 365 Backup & Restore

A simple tool to Backup Office 365/Exchange mailboxes to PST & Restore them