Alan here. In this guide we will be going through how to delete users and share their mailbox with another user. This is a must if you have someone leave but you want to keep their emails accessible for other users. This will also free up a license for another user. You can just remove their Microsoft365 license but their emails become inaccessible and are deleted after 30 days, the following method will permanently archive their emails for free.
This process can only allow one user to share the mailbox but we can add more users later using another one of our guides here.
First thing is we need access to the admin centre. If you don’t know how, we have a short guide here.
From the admin centre left side menu select users then active users.

Next we need to select the user we want to delete, in this case we will be removing Bob Jones. After selecting Bob Jones, we can click the delete user option.


A new window will slide in from the right after clicking delete user. This is where you can choose what happens to their mailbox delegate permissions, OneDrive files and mailbox. In this case, we will giving me access to Bob’s emails.

When the give email access to another user box it selected, the link to perform this action appears below. We click the blue text to continue.

This will open a new window from the right. Using the field, we can choose who will have access to Bob’s inbox. In this case, I will be giving myself access to the mailbox. When the user is selected, click next.


The next page will allow us to change the name of the mailbox, we will be leaving it as default in this example. Click next when you are finished.


The next page allows us to setup automatic replies. We can edit the content of the automatic reply and the conditions for the automatic reply. in our case, the message is fine but we want it to be sent to inside and outside of the organization.

After selecting the option, we can choose the same message or make a different message for inside or outside the organization using the new tick box that appears. We will be using the same message for inside and outside so I will leave the box unticked. When finished, click next.


The next window will allow us to change the email aliases, we will be leaving them alone in this instance. Click next when finished.


The last page will let us review our choices. Verify that this is correct for you then click Transfer ownership.


This will take you back to the delete user page. The new information will be filled in next to the selected options. Verify this is correct for you then click Assign and convert.

The final screen will confirm the new settings. Click close to finish.

Now we are back to the Active users screen, Bob’s account will show as Unlicensed. This means that his login information will no longer work.

For Outlook for Windows 10 Bob’s mailbox will show up for the chosen user automatically after some time. The Outlook web app is not as simple, the mailbox will need to be activated manually. We have a guide on how to do this here.