Troubleshoot shared mailboxes in new Outlook

Shared mailboxes are used when multiple people need access to the same mailbox. This setup is useful for emails dedicated to company information, support, reception desk, or other functions that multiple people share. An administrator can grant users permission to send email from the shared mailbox. This feature is useful for help and support mailboxes, allowing emails to be sent from "Contoso Support" or "Building A Reception Desk."

For more information about shared mailboxes, see About shared mailboxes

Use default OWAMailboxPolicy

This example enables the new Outlook for Windows for all mailboxes, including shared mailboxes in the organization:

Get-OwaMailboxPolicy | Set-OwaMailboxPolicy -OneWinNativeOutlookEnabled $true

For detailed syntax and parameter information, see Get-OwaMailboxPolicy and Set-OwaMailboxPolicy.

Use custom OWAMailboxPolicy

If only a subset of users within your organization use new Outlook and shared mailboxes, you need to create a custom OWAMailboxPolicy. For more information, see Create a mailbox policy in Exchange Online for Outlook on the web and the new Outlook for Windows

PowerShell

Create the policy by using the following syntax:

New-OwaMailboxPolicy -Name "<Unique Name>"

This example creates a mailbox policy for Outlook on the web and the new Outlook for Windows named SharedMailboxPolicy.

New-OwaMailboxPolicy -SharedMailboxPolicy

Enable OneWinNativeOutlookEnable:

Set-OWAMailboxPolicy “SharedMailboxPolicy” -OneWinNativeOutlookEnable $true

Confirm OneWinNativeOutlookEnable is applied to the new policy:

Get-OWAMailboxPolicy SharedMailboxesPolicy | FL *onewin*

Apply the new OWAMailboxPolicy on the shared mailbox:

Set-CASMailbox -<sharedmailbox Identity> -OWAMailboxPolicy “SharedMailboxPolicy”

With this newly applied OWAMailboxPolicy, users can access and add shared mailboxes using new Outlook.