Patrick Klingele-Bechinger, Escalation Engineer, Exchange Server Support

Mark Johnson, Sr. Technical Writer, Exchange Online

In the current version of Exchange Online for Microsoft Office 365, you have to use the Windows PowerShell command line to create and configure shared mailboxes. Using PowerShell, you have to perform these steps:

  • Create a shared mailbox.
  • Configure the quotas for the new shared mailbox.
  • Assign the FullAccess permission so that security group members can open the shared mailbox.
  • Assign the SendAs permission so that security group members can send messages from the shared mailbox.

To make this task a lot easier, we created a GUI-based tool you can use to create and configure a shared mailbox, and then assign permissions to a security group so members can open the shared mailbox and send messages from it. It’s an easy, three-step process:

  1. Download the Office 365 Shared Mailbox Tool.
  2. Create a security group and add members.
  3. Run the Office 365 Shared Mailbox Tool to create and configure a shared mailbox.

For more information about using shared mailboxes, see Set Up a Shared Mailbox.

Step 1: Download the Office 365 Shared Mailbox Tool

Download the SharedMailboxTool.zip file posted on the Downloads forum. This .zip file contains two files:

  • SharedMailboxTool.ps1   This is PowerShell (PS1) script for the Office 365 Shared Mailbox Tool.
  • StartSharedMailboxTool.bat   This is a DOS batch (.bat) file that you use to launch the Office 365 Shared Mailbox Tool.

After you download the .zip file, extract the two files to the same folder.

Step 2: Create a security group and add members

The Office 365 Shared Mailbox Tool assigns a security group the permission to access and send mail from the new shared mailbox. You can’t use the tool to assign permissions to an individual user. To create a security group and add members:

1. Start the Exchange Control Panel (ECP) and create a new distribution group:

  • Office 365 for professionals and small businesses   In the Office 365 portal, on the Admin Overview page, under Outlook, click Distribution groups. On the Distribution Groups page, click New.
  • Office 365 for enterprises   In the Office 365 portal, on the Admin Overview page, under Exchange, click Manage, and then select Manage My Organization > Users & Groups > Distribution Groups > New.

2. Specify a display name, alias, and e-mail address.

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.

For more information about security groups in Exchange Online, see Create a Security-Enabled Distribution Group.

Step 3: Run the Office 365 Shared Mailbox Tool to create and configure a shared mailbox

Now you’re ready to create a new shared mailbox and assign permissions to allow access to it by members of the security group you created in step 2. Here’s how:

1. In the folder where you extracted the files in the SharedMailboxtool.zip file, double-click StartSharedMailboxTool.bat

Note: If the Office 365 Shared Mailbox Tool doesn’t start, you may need to configure the execution policy on your computer. To do this, run the following command in Windows PowerShell and then start the shared mailbox tool.

Set-ExecutionPolicy RemoteSigned

2. In the Office 365 Administrator Credentials window, enter the user ID and password for an administrator account in your Office 365 organization, and then click OK. It might take a few minutes before the next window is displayed.

3. In the Office 365 Shared Mailbox Tool window, enter the following information:

  • The name for the shared mailbox. This name appears in the address book, on the To: and From: lines in e-mail, and in the Mailboxes list in the ECP.
  • The alias for the shared mailbox. The e-mail address for the new shared mailbox consists of the alias on the left side of the @ symbol and your domain name, like fourthcoffee.com, on the right side.
  • The name of the security group that will be assigned permissions to the shared mailbox. You can use the security group’s display name or alias.

4. Click Create to create the shared mailbox and assign permissions to the specified security group.

That’s it. Click Refresh on the Mailboxes page in the ECP to display the new shared mailbox. It may take up to 60 minutes before members of the security group can access the new shared mailbox.

Next steps

  • If you want to see what security groups are assigned permissions to a shared mailbox, click the Shared Mailbox Permissions tab in the Office 365 Shared Mailbox Tool. Enter the name or alias of a shared mailbox, and then click View Permissions. The tool displays the security groups that are assigned permissions to the shared mailbox and the specific permissions assigned to each security group.
  • To assign permissions to another security group to access a shared mailbox that you’ve created using the Office 365 Shared Mailbox Tool, you have to use PowerShell. See steps 3 and 4 in Set Up a Shared Mailbox.
  • Let users know how to open the shared mailbox using Outlook Web App. Point them to this page: Userfriendly Shared Mailboxes in OWA in Office 365.