Converting a user to a shared mailbox is an optimal scenario in most situations. Whether a temporary employee that may come back or a previous employee you want to refer to their e-mails later, but not tie up a license unnecessarily, a shared mailbox is the perfect solution.

There are a couple of important things to note.

  • The user you are converting needs to be an active, licensed mailbox. Do not preemptively remove their account or licenses. You actually never want to remove the account, as it provides the anchor all of this.
  • Shared mailboxes can, as of the time of this article, have up to 50GB of data without a license. If the box is larger than that, you will not be able to remove any licenses on the account after conversion.
  • Same as point one, I just can’t stress enough to not delete the user’s account.  It needs to remain in active directory.


The first thing you need to do is load the Office 365 Admin Center.

Under the recipients header, click on mailboxes.

Select the mailbox to be converted and click on Convert under the ‘Convert To Shared Mailbox’ header.

Click Yes to begin the conversion process. A modal will open showing you the status of the conversion.

Once the box has been converted, you can remove the licenses from the account that are no longer needed.

You can give a user access to this box by going to the admin console, clicking groups and then shared mailboxes.

Once selecting the shared mailbox, you will find some configuration options including members, where you can grant users access to this box.