When somebody leaves, the goal is to keep everything they created and remove everything they can reach — in that order, and on the day they go.
First action, and the only urgent one. Blocking sign-in without revoking the active sessions leaves them signed in on their own devices until the tokens expire.
Consider a shared-mailbox conversion or delegated access after checking retention, capacity, and licensing. Colleagues still need their own licensed Exchange Online mailboxes. Review external forwarding as part of offboarding.
Work in their OneDrive is theirs by storage but yours by ownership. We transfer what the team needs into SharePoint before the account is removed, because it does not survive deletion indefinitely.
Team sites, shared mailboxes, Teams memberships, and any app that used their account. This is where old access quietly survives an offboarding.
Only after mail and files are secured. Removing a licence early is the usual cause of losing a leaver's data.
A shared-mailbox conversion can preserve mail and the address. Check retention requirements, the 50 GB unlicensed limit, and advanced-feature licensing before removing a licence. Delegates need their own licensed Exchange Online mailboxes.
OneDrive contents are retained for a limited period after the account is deleted and then removed. Anything the business needs should be moved into SharePoint during offboarding rather than left to that clock.
Within business hours, quickly — blocking sign-in and revoking sessions is a small change. For a departure that has to happen at a specific moment, phone us and tell us the time in advance so it is not sitting in a queue.
Once their mail and files are secured, yes. We would rather carry a licence for a few extra days than delete the only copy of something you needed.
Tell us before the last day, not after. If the departure is not amicable, phone us so sign-in is blocked at the moment you need it rather than the next business morning.
If the fault turns out to be in the Microsoft service rather than your setup, we take it from there — you keep one point of contact.