Convert a user mailbox to shared in Exchange and Microsoft365

Multiple users can access shared mailbox in return. the opposite of a common user mailbox, a shared mailbox account is disabled in Active Directory and cannot be used for interactive sign-in. This article describes how to convert a normal user mailbox to a shared mailbox in on-premises Exchange Server and Microsoft 365.

When you convert a user mailbox to a shared mailbox, only the mailbox type is changed. All existing e-mail messages and calendar items, mailbox and folder permissions, as well as mailbox rules are maintained.

You may need to convert a user mailbox to a shared mailbox when:

  • If you want to share a mailbox with multiple users, use a shared calendar when scheduling;
  • The user leaves the organization and you want to share the mailbox contents with the remaining employees;
  • No separate license is required for a shared mailbox

How to convert a user mailbox to a share on Exchange Server with PowerShell?

In on-premises Exchange Server 2019/2016/2013, you can convert a user mailbox to a shared mailbox by using set-mailbox PowerShell cmdlet. Use the below syntax:

Set-Mailbox -Identity <MailboxIdentity> -Type <Regular | Room | Equipment | Shared>

Open the PowerShell console and connect to your Exchange server. Check mailbox type with command:

Get-Mailbox -Identity a.shepherd| Format-Table Name, RecipientTypeDetails

PowerShell: Get-Mailbox Type

This is a normal user mailbox (UserMailbox,

To change it to a shared mailbox, run the following command:

Set-Mailbox a.shepherd -Type Shared

The mailbox type has changed to SharedMailbox.

PowerShell: Convert a User Mailbox to a Share Type

To convert multiple user mailboxes to shared mailboxes at once, create a CSV file with the list of users (remember to add E-mail line for the first line of the file). Then import the CSV file and change the mailbox type:

Import-CSV C:\Reports\EXCH\user_to_shared_mailbox.csv | foreach {Get-Mailbox -Identity $_.Email | Where-Object {$_.RecipientTypeDetails -eq "UserMailbox"} | Set-Mailbox -Type Shared}

Do not delete the user account in AD just because the public mailbox is associated with it.

If you want to convert a shared mailbox back to a user’s mailbox, run this command:

Set-Mailbox a.shepherd -Type Regular

If you have a hybrid Exchange configuration, you’ll need to migrate your mailboxes to on-premises Exchange, convert them, and then bring them back to Microsoft 365.

Converting a User Mailbox to a Shared Mailbox in Exchange Online (Microsoft 365)

In Exchange Online, you can convert a user mailbox to a shared mailbox by using the Exchange Admin Center (EAC) or PowerShell.

    1. Sign up Sign In Exchange Admin Center;
    2. go for The recipient , mailbox,
    3. Select the user whose mailbox you want to convert;
    4. navigate to Other tab and click convert to shared mailbox,
    5. Confirm mailbox conversion;
    6. If the mailbox size is less than 50 GB, you can remove its Microsoft 365/AzureAD license.
      The size of a shared mailbox without a license cannot exceed 50 GB. Check current Exchange mailbox size and clear its contents if it exceeds 50 GB.

Exchange Admin Center (Microsoft 365) - Convert shared mailbox

Additionally, you can convert user mailboxes to shared mailboxes by using PowerShell. Connect to your Microsoft 365 tenant using the EXO PowerShell module:


To change the mailbox type shared mailboxRun the command below:

Set-Mailbox –Identity a.shepherd -Type Shared

You can convert it back the same way:

Set-Mailbox –Identity a.shepherd -Type Regular

Assign licenses to mailboxes within 30 days.

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