They came back. Their data did not.
A former employee returns after a few months. The account is re-licensed, or a new one is created with the same name, and on the first morning Outlook is empty, OneDrive shows "The site is archived", and the Teams chats from their previous stint are nowhere. An administrator on Microsoft Q&A described exactly this in August 2026: an employee back after five months, the OneDrive archived, and IT weighing up a new account and a manual migration of whatever could be found.
What a returning employee gets back depends entirely on two things: what was done to the account when they left, and how long ago that was. This page sets out the four common offboarding paths and what each leaves behind, then the recovery route for each.
What survives, by offboarding path
| What was done when they left | Mailbox | OneDrive | Teams chats |
|---|---|---|---|
| Account deleted, back within 30 days | Restorable in full. Microsoft: "the account and all associated data are restored" and "their mailbox is fully restored." | Restored with the account | Restored with the mailbox |
| Account deleted, back after 30 days | Permanently deleted, unless a retention policy or hold made it an inactive mailbox, in which case an administrator can recover it | Kept for the OneDrive retention setting, 30 days by default and configurable up to 3,650 days, then deleted | Gone with the mailbox, unless retained in an inactive mailbox |
| Account kept, licence removed | Microsoft: "the former employee's email, contacts, and calendar are retained for 30 days, and are then deleted permanently", unless a hold was in place | Read-only at day 60, archived at day 93, subject to deletion at 365 cumulative unpaid days. Assigning a licence reactivates it, without a fee, within 24 to 48 hours | Gone with the mailbox |
| Mailbox converted to a shared mailbox | Kept. It can be converted back to a user mailbox once a licence is assigned | As for licence removed | Chat records stay with the mailbox and follow it |
The rows that catch people are the second and third. A deleted account is only restorable for 30 days, and after that the mailbox is gone for good unless something held it. An account left in place without a licence keeps its OneDrive for a long time, but the mailbox contents still go after 30 days, which is the opposite of what most administrators assume.
How to give a returning employee their old data
Take the route that matches the row above.
Deleted less than 30 days ago. In the Microsoft 365 admin center, go to Users, then Deleted users, select the account and choose Restore user, then assign a licence. Microsoft's tip: make sure a licence is available first. If a new account was created for the returning employee with the same name, the restore reports a user name conflict; rename the new account or give the restored one a different address, then merge.
Deleted more than 30 days ago, with a hold. The mailbox became an inactive mailbox when the account was deleted. An administrator can recover it as a new mailbox for the returning employee, or restore its contents into the mailbox their new account already has. The inactive mailbox itself stays preserved for as long as the hold requires.
Deleted more than 30 days ago, no hold. The mailbox is gone and support cannot bring it back. The OneDrive may survive if the OneDrive retention setting was longer than the gap; check the deleted user's OneDrive in the SharePoint admin center before assuming. Otherwise what remains is whatever a manager was given access to at offboarding, a PST exported at the time, or an archive taken before the account was removed.
Account kept, licence removed. Assign a licence to the existing account. The OneDrive reactivates automatically within 24 to 48 hours with no reactivation fee, provided the account is under 365 unpaid days. The mailbox, however, was deleted 30 days after the licence went unless a hold was in place, and the new licence creates an empty one. If the admin center tells you a fresh mailbox is being created because the old one was inactive, that is what has happened: the original mailbox is no longer available to reconnect.
Converted to a shared mailbox. Convert the shared mailbox back to a user mailbox and assign the licence. The mail, calendar and contacts return intact. Then deal with the OneDrive as for a removed licence.
If the OneDrive shows "The site is archived" and the user account itself was deleted, reactivation goes through Reports, then OneDrive accounts, in the SharePoint admin center, is billed at $0.60 per GB, and keeps the account active for only 30 days. The full procedure and the fees are on unlicensed OneDrive accounts.
The Teams chats
Chat messages are stored as compliance copies in the mailboxes of everyone in the conversation, so the returning employee's own copies followed their mailbox: restored with it inside 30 days, preserved in an inactive mailbox under a hold, or gone with it otherwise. Their colleagues' copies of the same chats are unaffected. Details, including the eDiscovery route, are in Teams chat history after a colleague leaves.
What an archive at offboarding changes
Every path above depends on something having been done before the account went, and on the return happening inside a window. An archive removes both conditions.
Chipmunk watches Microsoft Entra ID and, when an account is disabled, archives the mailbox with its attachments, the OneDrive files and the Teams chats, channels and shared files into an Azure Blob Storage account in your own subscription. The licence is then reclaimed. When the person comes back, a full restore rehydrates the entire archive into their new live account, or onto a file share, and a granular restore pulls back individual emails, files or chats by keyword search if only some of it is wanted. Nothing depends on which plan they held, whether a hold was set, or how long they were away.
Chipmunk is not a Purview hold and does not integrate with Purview eDiscovery. Where legal needs eDiscovery inside Microsoft 365 for particular former employees, keep the hold on those accounts and run the archive alongside it. It costs $200 a month plus $10 per archived user per year, with the Azure storage billed by Microsoft on your own invoice.
Frequently asked questions
Q: Can I restore a deleted Microsoft 365 user after 30 days?
A: No. Microsoft's restore window is 30 days from deletion, and after that the account and its mailbox are permanently deleted. If a retention policy or hold applied to the mailbox while the account was licensed, the mailbox survives as an inactive mailbox and an administrator can recover it separately.
Q: Will a rehired employee get their old OneDrive back?
A: If the account was kept and only the licence removed, yes: assigning a licence reactivates the OneDrive automatically within 24 to 48 hours with no fee, as long as the account is under 365 unpaid days. If the account was deleted, the OneDrive is kept only for the OneDrive retention setting, 30 days by default, and is then deleted.
Q: Why is a rehired employee's mailbox empty?
A: Because the original mailbox was deleted. That happens 30 days after the account is deleted, and also 30 days after the licence is removed from an account that is kept, unless a hold was in place. The new licence creates a fresh, empty mailbox. Any notice that a fresh mailbox is being created because the old one was inactive means the original can no longer be reconnected.
Q: Can I convert a shared mailbox back to a user mailbox?
A: Yes. A mailbox that was converted to shared at offboarding can be converted back to a user mailbox once a licence is assigned, with its mail, calendar and contacts intact.
Q: How do I restore an inactive mailbox to a returning employee?
A: An administrator can either recover the inactive mailbox as a new mailbox for the returning user, or restore its contents into the mailbox the user's new account already has. Both keep the inactive mailbox preserved under its hold.
Next steps
Related reading
Mark Smith co-founded SmiKar Software in 2015 and has spent the past decade helping organisations solve Microsoft 365 data management challenges. He works with the SmiKar team to build solutions for SharePoint archiving, storage optimisation, governance and compliance, supporting customers from growing businesses through to Fortune 500 enterprises.
More about SmiKar
