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Set Up a Shared Mailbox


Applies to: Office 365 for enterprises, Live@edu

Topic Last Modified: 2012-07-31

A shared mailbox is a mailbox that multiple users can open to read and send e-mail messages. Shared mailboxes allow a group of users to view and send e-mail from a common mailbox. They also allow users to share a common calendar, so they can schedule and view vacation time or work shifts. Why set up a shared mailbox?

  • It can provide a generic e-mail address, such as or, which customers can use to inquire about your company.

  • It allows staff in departments that provide centralized services to employees, such as the help desk, human resources, or printing services, to respond to employee questions.

  • It allows multiple users to monitor and reply to e-mail sent to an e-mail address, such as a help desk.

  • In a school environment, it provides students and parents with an entry point to different school departments, such as academic departments, library services, or financial aid.

Shared mailboxes in Microsoft Office 365

In Office 365, shared mailboxes don’t require a license. However, each user who accesses a shared mailbox must have a user subscription license. Users with Exchange Online Kiosk subscriptions can’t access shared mailboxes. Also, shared mailboxes can’t be used to archive e-mail, except for the messages that are actually sent to or received from the shared mailbox.

If your organization requires any of the following functionality for a shared mailbox, you have to assign it an Exchange Online (Plan 1) user subscription license:

  • A shared mailbox that is larger than 5 GB, which is the maximum size allowed for shared mailboxes

  • The ability to enable an archive mailbox for the shared mailbox

If, in addition to this functionality, your organization has to put a shared mailbox on litigation hold, you have to assign it an Exchange Online (Plan 2) user subscription license.

For more information, see Manage licenses in Office 365 for enterprises.

Watch this video to learn how to set up a shared mailbox

Before you begin

To learn how to install and configure Windows PowerShell and connect to the service, see Use Windows PowerShell in Exchange Online.

Create and configure a shared mailbox with PowerShell

After you create a shared mailbox, you have to assign permissions to all users who require access to the shared mailbox. Users can't sign in to the shared mailbox. They have to sign in to their own mailbox and then open the shared mailbox to which they've been assigned permissions.

Here's how to use PowerShell to create and configure a shared mailbox for the Corporate Printing Services department at Contoso Corporation.

  1. Create a shared mailbox   To create the shared mailbox for Corporate Printing Services, run one of the following commands:


    Office 365


    New-Mailbox -Name "Corporate Printing Services" -Alias corpprint -Shared
    Set-Mailbox corpprint -ProhibitSendReceiveQuota 5GB -ProhibitSendQuota 4.75GB -IssueWarningQuota 4.5GB


    Microsoft Live@edu


    New-Mailbox -Name "Corporate Printing Services" -Alias corpprint -Shared


    The new shared mailbox is displayed in the Mailboxes list in the Exchange Control Panel.

  2. Create a security group for the users who need access to the shared mailbox   In the Exchange Control Panel, create a security group for the staff who need access to the shared mailbox for Corporate Printing Services.

    1. Select My Organization > Users & Groups > Distribution Groups > New.

    2. Specify a display name, alias, and e-mail address. In this example, we'll use Printing Services Staff, corpprintDG, and

    3. Select the Make this group a security group check box.

    4. In the Ownership section, click Add to add an owner, if necessary.

    5. In the Membership section, click Add.

    6. In the Select Members page, select the users you want to add. When you are finished, click OK.

    7. On the New Group page, click Save.

      Note   After you create a security group, the membership is closed. When membership is closed, only group owners can add members to the security group, or owners have to approve requests to join the group. Additionally, only group owners can remove members from the security group.

  3. Assign the security group the FullAccess permission to access the shared mailbox   To enable members of the Printing Services Staff security group to open the shared mailbox, read e-mail, and use the calendar, run the following command:

    Add-MailboxPermission "Corporate Printing Services" -User corpprintDG -AccessRights FullAccess
  4. Assign the security group the SendAs permission to the shared mailbox   To enable members of the Printing Services Staff security group to send e-mail from the shared mailbox, run the following command:

    Add-RecipientPermission "Corporate Printing Services" -Trustee corpprintDG -AccessRights SendAs

Note   It may take up to 60 minutes until users can access a new shared mailbox or until a new security group member can access a shared mailbox

Use the Office 365 Shared Mailbox Tool

We created a GUI-based tool to make it easier to create and configure shared mailboxes. After you download the shared mailbox tool and create a security group, you can run the tool to create a shared mailbox and assign the FullAccess and SendAs permissions to a security group. See Create Shared Mailboxes with GUI-based Tool.

Next steps

  • Assign an Exchange Online (Plan 1) or Exchange Online (Plan 2) license to a shared mailbox if you need additional functionality. See Manage licenses in Office 365 for enterprises.

  • Let users know how to open the shared mailbox using Outlook Web App. Point them to this topic: Open Another Mailbox

  • Let users know they can view and use the calendar in the shared mailbox. Each user can schedule events or enter their vacation or out-of-office time.

  • By default, security-enabled distribution groups are displayed in the shared address book. However, you may not want users to send e-mail to this type of group because its purpose is to assign permissions to a shared mailbox. To help prevent users from sending e-mail to a security-enabled distribution group, you can hide it from the shared address book.

    To hide a group, just select it in the Groups list, click Details, and select the Hide this group from the shared address book check box.

    Alternatively, you can restrict who can send messages to the group. For example, you can allow only members to send messages to the group. To do this, configure the Delivery Management section on the group's properties page. See Change Distribution Group Properties.

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