How to convert a user mailbox to a shared mailbox in Microsoft 365

This article explains how to convert an Exchange Online user mailbox to a shared mailbox using the Exchange admin center (EAC) and Exchange Online PowerShell. It also shows how to convert multiple user mailboxes to shared mailboxes in Microsoft 365 in just a few clicks using ManageEngine M365 Manager Plus, a dedicated Microsoft 365 administration tool.

Method 1: How to convert a user mailbox to a shared mailbox using the Exchange admin center (EAC)

Prerequisites

You must have the Exchange Administrator or Global Administrator role.

Steps

1. Log in to EAC and navigate to Recipients > Mailboxes.
2. Locate the user mailbox you wish to change. You can use the Filter button to narrow down the list.
3. Click the display name of the mailbox to open the details pane.
4. On the pane that appears, navigate to the Others tab and click Convert to shared mailbox.
5. Click Confirm in the confirmation dialog box.
6. Once the successful conversion message appears, you can use the Microsoft 365 admin center to remove the license from the original user account.

Limitations to consider

You will have to perform the same set of steps for every user mailbox you want to convert to a shared mailbox. To convert multiple user mailboxes to shared mailboxes, you can resort to complex Exchange Online PowerShell scripts, or you can try out M365 Manager Plus, which would only take a few clicks with its user-friendly interface.

Method 2: How to convert a Microsoft 365 user mailbox to a shared mailbox using Exchange Online PowerShell (Set-Mailbox)

Before using Exchange Online PowerShell, verify that:

Prerequisites

Before using Exchange Online PowerShell, please verify that:

1. The Exchange Administrator role is applied to the account you use to sign in to Exchange Online PowerShell.
2. You are connected to the Exchange Online PowerShell module.
   1. To check if the Exchange Online PowerShell module is installed, use this script:
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      Get-Module -ListAvailable ExchangeOnlineManagement

   2. If it does not return a value, you will have to install the module. To install the Exchange Online PowerShell module, execute this script:
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      Install-Module ExchangeOnlineManagement -Scope CurrentUser

   3. To connect to Exchange Online PowerShell, run this script:
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      Connect-ExchangeOnline

Convert a user mailbox to a shared mailbox with Set-Mailbox

The Set-Mailbox cmdlet is used to modify mailbox properties in Exchange Online. To convert a user mailbox to a shared mailbox, modify the Type attribute to Shared as shown in the Exchange Online PowerShell cmdlet.

Set-Mailbox -Identity "james@yourdomain.com" -Type Shared

After the conversion is complete, remove the Microsoft 365 license from the user account to avoid unnecessary licensing costs.

A use case for the Set-Mailbox cmdlet

An IT administrator needs to convert multiple user mailboxes to shared mailboxes as a part of their offboarding process, ensuring that users' email data remains accessible to teams without maintaining individual licenses.

You can use the following Exchange Online PowerShell script to convert a filtered list of user mailboxes to shared mailboxes:

$UserMailboxes = Get-Mailbox -RecipientTypeDetails UserMailbox -ResultSize Unlimited |
Where-Object { $_.DisplayName -like "*Sales*" }

foreach ($Mailbox in $UserMailboxes) {
    Set-Mailbox -Identity $Mailbox.ExternalDirectoryObjectId -Type Shared
}

Method 3: How to convert a user mailbox to a shared mailbox using M365 Manager Plus

Steps

1. Log in to M365 Manager Plus.
2. Navigate to Management > Exchange Online > User Mailbox Management and select Mailbox Conversion.
3. From the Convert to drop-down menu, select Shared mailbox.
4. Enter the display names of the user mailboxes you want to convert and click Find. Alternatively, upload a CSV containing mailbox details using the CSV Import option.
5. Review the selected mailboxes and click Apply to complete the conversion.

Monitor your Exchange Online shared mailboxes and more

M365 Manager Plus’ shared mailbox management capabilities help you view, monitor, and control shared mailboxes across your Microsoft 365 environment. The solution simplifies permission audits, highlights inactive mailboxes, and provides proactive alerts.

Important tips

Frequently asked questions