One of our team members left the company last month and I removed their Microsoft 365 account. Now the manager needs some old emails from that person for a client handover. When I look in the admin center the user is gone, but I have read the mailbox may still exist as an "inactive" mailbox. How do I actually get to that data? Do I need to buy a new license, and is there a time limit before it is gone for good?
How to Access an Inactive User Mailbox in Office 365
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Community Member July 28, 2026
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5 Answers
Good news, the data is very likely still there. In Microsoft 365 a mailbox becomes an inactive mailbox when a hold (Litigation Hold or a retention policy) was applied to it and then the user account was deleted. The contents are preserved for the full duration of that hold, so the mailbox is not lost just because the account is gone.
One thing to check first: if you simply deleted the account with no hold in place, the mailbox is only soft deleted and kept for 30 days. Inside that window the fastest fix is to restore the user from Deleted Users in the admin center, which brings the mailbox back attached to the account. Past 30 days with no hold, the data is purged, so the inactive-mailbox route only works when a hold or retention policy was set before deletion.
To find the inactive mailbox, connect to Exchange Online PowerShell and list them:
Get-Mailbox -InactiveMailboxOnly | Format-List Name,PrimarySmtpAddress,DistinguishedName,ExchangeGuid
Note the DistinguishedName or ExchangeGuid of the one you need. There is no visible "inactive" flag in the normal admin center, which is why people think the mailbox is gone. It is not, it is just hidden from the standard views and only reachable through PowerShell or eDiscovery content search.
Now decide between recover and restore, they are different:
Recover converts the inactive mailbox into a brand new mailbox with the same folder structure, then links it to a new user account. After recovery the inactive mailbox no longer exists. This suits the case where someone rejoins or a replacement takes the same role. After recovering you must assign a license to activate the new account.
Restore merges (copies) the inactive mailbox content into an existing active mailbox, for example the manager's own mailbox or a shared mailbox. The inactive mailbox stays in place afterwards. For a one-off client handover where the manager just needs to read the old mail, restore into a shared mailbox is usually the cleaner choice.
To restore into an existing mailbox, grab the inactive mailbox object and run a restore request:
$im = Get-Mailbox -InactiveMailboxOnly -Identity "user@yourdomain.com"
New-MailboxRestoreRequest -SourceMailbox $im.DistinguishedName -TargetMailbox target@yourdomain.com -AllowLegacyDNMismatch
The old messages land in the target mailbox and the source inactive mailbox is untouched. On licensing: an inactive mailbox itself does not consume a license. You only need a license on the new account if you go the recover route, or on the target mailbox that receives a restore.
One caveat worth flagging before you start: if the inactive mailbox has an auto-expanding archive, it cannot be recovered or restored with these cmdlets. In that case the supported path is to use eDiscovery content search to export the data, which is meant for compliance retrieval rather than as a backup method. For a normal mailbox without auto-expanding archive, the recover or restore steps above are all you need.