You might start seeing calls in the future that messages “sent as” the username of a shared mailbox are being placed in the Sent Items of the person who sent the message instead of the Sent Items of the shared mailbox.

  • I,e. Angela Krewda & Trish Glab have “full” & “send-as” access to the International Admissions mailbox; when Trish sends as the International Admissions user (setting the From field to that user), the sent messages are put in her Sent Items folder.  When Angela does the same thing, the message shows in the International Admissions’ Sent Items.


This isn’t really new behavior, but Outlook 2007 SP2 allowed you to set a registry key to have the sent message get placed in the shared mailbox’s Sent Items by default.

Outlook 2010 and higher has changed that, of course – the default sets it back to putting the sent messages in your own Sent Items folder.  There’s a method to fix that, but you need the following:

  • Cached mode enabled for the user’s profile in Outlook
    • Click on File
    • Select Account Settings --> Account settings
    • With the Email tab selected, click the Change button
    • Make sure there is a check mark beside Use Cached Exchange Mode
    • If it is there, click Cancel, you are done.  If you had to select the option, then click Next and Finish
    • Close the account Settings window
  • Edit the Registry to enter a new DWORD key
    • Close Outlook
    • Click Start and type Regedit in the search field and hit Enter
    • Navigate to, and select - HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Preferences\
    • In the right pane, right-click and select New --> DWORD
    • The value/title is DelegateSentItemsStyle
    • Right-click on the new keyword and select Modify
    • Enter 1 in the Value Data: field, click OK
  • Restart Outlook


After that, items sent as a shared mailbox user will in fact be put in that shared mailbox’s Sent Items.  If you don’t set Outlook to Cached Mode, the items will stay in the person’s Outbox and never clear, and never show up in the right Sent Items folder.

Please see this article if they want the Deleted items to also appear in the appropriate folder.

References:
https://support.microsoft.com/en-ca/help/2843677/messages-sent-from-a-shared-mailbox-aren-t-saved-to-the-sent-items-fol