Save Sent Email Within Shared Mailbox in Office 365

Purpose

When sending a message as another user or on behalf of the user, the sent message isn’t saved to the Sent Items folder of the shared mailbox. Instead, it’s saved to the Sent Items folder of your own mailbox. These instructions will change this behavior so that mail sent on behalf of a shared mailbox will populate inside that shared mailbox’s Sent folder.

Prerequisites

Exchange Online PowerShell module must be installed in PowerShell your application.

Solutions

At your computer launch PowerShell
Install the Exchange Online PowerShell module (if you don’t already have it)

Import-Module ExchangeOnlineManagement

Connect to Exchange Online

Connect-ExchangeOnline -UserPrincipalName navin@contoso.onmicrosoft.com

Using Exchange PowerShell, for emails Sent As the shared mailbox, run the following cmdlet:

set-mailbox <mailbox name> -MessageCopyForSentAsEnabled $True

Using Exchange PowerShell, for emails Sent On Behalf of the shared mailbox, run the following cmdlet:

set-mailbox <mailbox name> -MessageCopyForSendOnBehalfEnabled $True