Email Recovery

How to Manage Former Employee Mailboxes in Exchange Online

Camila Milosovich Oct 19, 2026 869 views

Question details

The user needs to securely manage and preserve the email data of a former employee before deleting their Exchange Online account.

How to Manage Former Employee Mailboxes in Exchange Online

Product: Exchange Online
Device & OS: not provided
Scenario: An employee is leaving the organization, and the admin needs to retain their emails, reassign mailbox access, and handle aliases without losing data.
Observed behavior: The goal is to safely transition the mailbox by converting it to a shared mailbox, configuring replies, and removing unnecessary calendar permissions before the account deletion.

Before you start

Ensure you have the necessary administrator privileges in Microsoft 365 or Exchange Online to modify user accounts, mailbox configurations, and alias settings.

Solution 1Recommended

Convert to a Shared Mailbox and Configure Access

This is the recommended approach to preserve email data, grant access to another user, and ensure continuous mail delivery without requiring an extra license.

By converting the former employee's mailbox into a shared mailbox, you retain all past emails while allowing a manager or replacement to access and monitor new incoming messages.

It is crucial to perform these steps before completely deleting the user account from your organization's directory.

Grant Access and Convert

Give an administrator or another authorized user access to the deleted user's email. Doing this converts the user's mailbox into a shared mailbox so the new owner can monitor incoming messages.

Update the Display Name

Change the display name of the shared mailbox so that it is easily identifiable in your Active users list (for example, append 'Shared' or 'Former' to the name).

Turn on Automatic Replies

Configure automatic replies to send different out-of-office or transition messages to people inside and outside your organization.

Clean Up Aliases

Remove any existing aliases (additional email addresses) from the user account. If you do not remove them now, you will have to wait for the 30-day retention period to pass before you can reuse those addresses.

Remove Calendar Permissions

Use the Exchange Online PowerShell command 'Remove-MailboxFolderPermission' to remove any existing calendar permissions tied to the former employee.

Convert to a Shared Mailbox and Configure Access

Mailbox Recovery Window: If you accidentally delete a user mailbox before converting it, the deleted mailbox is typically recoverable for 30 days by default.

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Frequently Asked Questions

What happens to a user's aliases when their Exchange Online mailbox is deleted?

If you delete a mailbox without removing its aliases first, you cannot reuse those email addresses until the 30-day deleted mailbox retention period has passed. It is strongly recommended to clean up aliases before deleting the account.

Can I recover an Exchange Online mailbox after it has been deleted?

Yes, by default, a deleted user mailbox in Exchange Online is recoverable for up to 30 days. After this retention period, the mailbox and its contents are permanently purged.

Why should I change the display name of a former employee's mailbox?

Changing the display name helps administrators and other employees easily identify that the account is now a shared mailbox for a former employee, keeping the Active users list organized and preventing confusion.

Migration & Recovery