When an employee leaves, the most expensive mistake isn't failing to deactivate the account – it's letting the license keep running. It gets billed month after month even though no one is using it. This guide shows you the clean process: block access, back up data, keep the mailbox, revoke the license – traceable and without data loss.
Why Offboarding Is a License Issue
Locking the account feels "done." But it isn't: a blocked identity keeps its assigned license, and that keeps costing money. This is exactly how the "orphaned accounts" arise that make up the biggest savings potential in every tenant that has grown over time. → Find unused licenses.
Microsoft describes the full process in a dedicated article series on removing former employees. The following four steps are the essence of it – with a focus on the license.
Step 1 – Block Access Immediately
Security first: reset the password, sign the user out of all sessions, and block sign-in. Microsoft recommends exactly this order, because blocking alone can take up to 24 hours – whereas resetting the password takes effect immediately.
Step 2 – Back Up Data
Before anything is removed: back up what you need. The mailbox, OneDrive files, and shared content should be handed over to a responsible person or exported. This step determines whether Step 4 is risk-free.
Step 3 – Keep the Mailbox Without Paying
If the mailbox needs to stay reachable (e.g., for customer inquiries directed at the person who left), convert it into a shared mailbox. According to Microsoft, all emails and calendar data are preserved in the process, and you can then remove the license – a shared mailbox under 50 GB doesn't need a paid license. Important: do not delete the account; it serves as the anchor for the mailbox.
Step 4 – Revoke the License
Now the actual money-saving step: revoke the license. When you remove it, Microsoft retains the mailbox data for 30 days and doesn't delete OneDrive files as long as the account exists – so the step is reversible if you did Step 2. You can reassign the freed-up license immediately or reduce your seat count.
The Checklist at a Glance
| Step | Action | Goal |
|---|---|---|
| 1 | Reset password, end sessions, block sign-in | Stop access immediately |
| 2 | Back up/hand over mailbox & OneDrive | No data loss |
| 3 | Mailbox → shared mailbox (if needed) | Reachability without a license |
| 4 | Revoke the license | Stop the costs |
Why This Has to Be a Fixed Process
A single, cleanly executed offboarding saves one seat. A firmly established offboarding process saves them all – for good. Without this step, the most common cause of excess cost keeps recurring. → The 10 most common causes of excessive costs.
To make sure no departure slips through, regular checks help: License Lens connects to your tenant in read-only mode and shows blocked accounts that still have an active license in seconds – the classic offboarding gaps. No changes, no stored employee data.
The big picture: Cutting Microsoft 365 license costs – the complete guide.