Compliance Problems

How to Troubleshoot Purview Exchange Legacy MRM Retention Policies

Kushani Nimanthika Oct 20, 2026 870 views

Question details

The user needs to troubleshoot a Microsoft Purview Messaging Records Management (MRM) retention policy that is failing to empty the Deleted Items folder in a test mailbox.

How to Troubleshoot Purview Exchange Legacy MRM Retention Policies

Product: Microsoft Purview / Exchange
Device & OS: not provided
Scenario: Verifying retention tags, policy assignments, and mailbox processing to ensure deleted items are automatically cleared.
Observed behavior: The MRM retention policy is assigned, but the Deleted Items folder is not being emptied as expected.

Before you start

Ensure you have Exchange Administrator permissions and access to Exchange Online PowerShell to verify mailbox policies and force mailbox processing.

Solution 1Recommended

Verify MRM Policy Settings and Force Mailbox Processing

Check that the retention tags are correctly configured and use PowerShell to manually trigger the Managed Folder Assistant.

Sometimes, retention policies do not apply immediately because the Managed Folder Assistant operates on a throttled schedule in Exchange Online. Verifying the policy assignment and manually forcing the assistant can resolve the delay.

Verify retention tag configuration

Log in to the Microsoft Purview compliance portal or Exchange Admin Center. Navigate to Data lifecycle management and verify that your retention tag specifically targets the 'Deleted Items' folder with the correct retention age and deletion action.

Check policy assignment

Ensure the retention policy containing your tag is explicitly assigned to the test mailbox. In the Exchange Admin Center, go to Recipients > Mailboxes, select the test mailbox, and verify the assigned retention policy under the Mailbox policies section.

Connect to Exchange Online PowerShell

Open PowerShell as an administrator and run 'Connect-ExchangeOnline' to authenticate with your Microsoft 365 admin credentials.

Force the Managed Folder Assistant

Run the command 'Start-ManagedFolderAssistant -Identity <mailbox_email_address>' to manually trigger the processing of the retention policy for the specific mailbox.

Microsoft Q&A Support: Because this issue involves complex Exchange Messaging Records Management, if the folder still does not empty after processing, it is recommended to request assistance in Microsoft Q&A under the Exchange Online Management or Exchange Server Management tags.

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Frequently Asked Questions

Why does the Managed Folder Assistant take so long to process?

The Managed Folder Assistant is a throttle-based background process in Exchange Online. Even after manually starting it with PowerShell, it may take several hours or up to a few days to fully evaluate and process items depending on server load.

How can I confirm which retention policy is assigned to a specific mailbox?

You can verify this in the Exchange Admin Center by navigating to Recipients > Mailboxes, selecting the user's mailbox, and checking the Mailbox policies tab. You can also run the 'Get-Mailbox -Identity <user> | Select RetentionPolicy' cmdlet in Exchange Online PowerShell.

Can personal retention tags override default retention policies?

Yes. If a user manually applies a personal retention tag to a specific folder or email, that tag will take precedence over the Default Policy Tag (DPT) assigned by the Exchange administrator.

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