Save sent items to a shared mailbox on Exchange (Microsoft 365) |

You can allow users to send e-mail on behalf of shared mailboxes in Exchange Server and Microsoft 365 (Exchange Online). However, such e-mail, once sent, will not be saved in sent items Folder of the shared (owner’s) mailbox. It is stored only in the Sent Items folder of your personal mailbox. This is very inconvenient when several users are working with the same shared mailbox, as it is not clear who has replied to incoming e-mail or sent a specific message.

Assume that your account has been granted Send As and/or Send on Behalf permissions to the Helpdesk shared mailbox. You should have copies of all e-mail that you (or other delegates) have provided on behalf of the shared mailbox in its Sent Items folder.

Connect to your on-premises Exchange server by using PowerShell:

$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri -Authentication Kerberos -Credential
Import-PSSession $Session

Or connect to Microsoft 365 by using the Exchange Online PowerShell (EXOv2) module:


To automatically save e-mail items sent through the Send to Sent Items folder in a shared mailbox, run the following command:

Set-Mailbox helpdesk -MessageCopyForSentAsEnabled $True

You can also save messages you’ve sent using Send on behalf of.

Set-Mailbox helpdesk -MessageCopyForSendOnBehalfEnabled $True

Check current settings:

Get-Mailbox helpdesk | select MessageCopyForSentAsEnabled, MessageCopyForSendOnBehalfEnabled

PowerShell: Enable mailbox options MessageCopyForSentAsEnabled and MessageCopyForSendOnBe halfEnabled

This cmdlet is available in Exchange Server 2013 CU9/2016/2019 and Exchange Online.

You can enable these options for all shared mailboxes:

Get-Mailbox -ResultSize unlimited -Filter {(RecipientTypeDetails -eq 'SharedMailbox')} | Set-Mailbox -MessageCopyForSendOnBehalfEnabled $true -MessageCopyForSentAsEnabled $true

You can also enable or disable this option using the Microsoft 365 admin center:

  1. Sign in to the Microsoft 365 admin center;
  2. Navigate to Teams and Groups -> Shared Mailboxes;
  3. Select the shared mailbox you want to configure;
  4. locate sent items section in the mailbox settings and click edit,
  5. There are two options available here:
    Copy items sent as this mailbox
    Copy items sent on behalf of this mailbox

    Microsoft 365: Enable Cc Sent Items for shared mailboxes

  6. Enable the options you want and save the changes.

possible to use MessageCopyForSendOnBehalfEnabled And MessageCopyForSentAsEnabled Parameters to copy only messages sent from the shared mailbox. If you want to save messages sent on behalf of a normal user mailbox (or for an Exchange Server 2010 mailbox), you need to enable the Outlook registry option Delegate SentItemsStyle (or convert a user mailbox to a shared mailbox).

Value name: DelegateSentItemsStyle
Value Type: REG_DWORD
Value: 1
  • Outlook 2016/2019/2021/365:
  • Outlook 2013:
  • Outlook 2010:

you can use Set-MailboxSentItemsConfiguration cmdlet to change Sent Item Retention settings for a mailbox on Exchange Server 2010 SP2 Update Rollup 4:

Set-MailboxSentItemsConfiguration helpdesk -SendAsItemsCopiedTo Sender -SendOnBehalfOfItemsCopiedTo SenderAndFrom

For this feature to work, Outlook must be online or in Cached Exchange Mode. The DelegateSentItemsStyle registry option must be disabled.

Now, when you send an e-mail on behalf of another mailbox, it will be saved in the Sent Items folder of the owner’s mailbox.

Outlook: Save a copy of sent messages to the owner's mailbox

If e-mail still does not appear in the Sent Items folder of the shared mailbox, verify that it is configured to receive e-mail only from authenticated users:

Get-Mailbox helpdesk | fl *auth*

RequireSenderAuthenticationEnabled : True

You can change this behavior as follows:

Set-Mailbox helpdesk -RequireSenderAuthenticationEnabled $false

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