Every month a few people leave our company and, as the tenant admin, I have to remove their Microsoft 365 accounts to free up licenses. Before I delete an account I want to keep the person's old emails somewhere safe and accessible in the tenant, ideally in an archive mailbox rather than a loose PST on my desktop. How do I archive a leaving user's mailbox properly? Does the archive need a separate license, and what happens to that archived data once the account is actually removed?
How to Archive a Departing User's Mailbox in an Office 365 Tenant
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CM
Community Member July 30, 2026
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5 Answers
There are two separate ideas here worth untangling, because "archive a user" can mean two different things in Microsoft 365.
The first is the archive mailbox (also called In-Place Archiving), which is a secondary mailbox attached to a live user. It gives extra storage and holds older mail without using primary mailbox space, but it belongs to an active account. The second is what you actually want for a leaving employee: retaining the mailbox after the account is deleted, which is done with a hold or retention policy, not with the archive feature. For a clean handover, you usually want both, enable the archive so nothing is scattered, then apply a hold so the data survives account deletion.
To enable the archive mailbox from the Exchange admin center: go to Recipients, then Mailboxes, select the user, open the Others tab, and under Mailbox archive choose Manage mailbox archive and turn it on. Or do it in PowerShell:
Enable-Mailbox -Identity user@yourdomain.com -Archive
Verify it actually provisioned by checking ArchiveGuid and ArchiveStatus, not just the UI. Once enabled, the default archive policy moves items older than two years into the archive automatically, and users can also drag mail there manually in Outlook or Outlook on the web.
On licensing, the archive is not free. You need an Exchange Online Plan 2 license, or an Exchange Online Plan 1 license with the Exchange Online Archiving add-on. Plan 1 gives a fixed archive size while Plan 2 and the archiving add-on provide auto-expanding archive, which grows in increments as it fills up. Archive mailboxes are only for internal users in your tenant, you cannot enable one for a guest or external user.
Here is the key point for a departing user. The archive mailbox on its own does not survive account deletion, and it is not a backup. When you remove the account, the mailbox (primary and archive together) is soft deleted and kept for only 30 days by default.
To keep the data long term, apply a Litigation Hold or a Microsoft 365 retention policy to the mailbox before you delete the account. A hold covers both the primary and the archive mailbox. With the hold in place, deleting the account converts it to an inactive mailbox and the content is retained for the full duration of the hold, so nothing is lost when the license is reclaimed.
Quick sequence to follow for each leaver: enable the archive if it is not already on, apply a retention policy or Litigation Hold to the mailbox, confirm the hold shows as applied, then remove the Microsoft 365 account to free the license. After that the data lives on as an inactive mailbox and stays searchable through Content Search in the Purview portal. If someone later needs the mail, you recover or restore that inactive mailbox rather than hunting for a PST. This keeps everything inside the tenant and auditable, with no loose files on anyone's desktop.