Hello,

By default, when you send or delete an item with Outlook, on a shared/delegated mailbox, those mails will go to your own sent items/deleted items folder. That’s not very convenient if your work in a team and someone need to takes over you a case you started. You can override this default behavior with two registry keys :

#Sent
New-ItemProperty -Path HKCU:\Software\Microsoft\Office\15.0\Outlook\Preferences -Name DelegateSentItemsStyle -PropertyType DWORD -Value 1 -Force
#Deleted
New-ItemProperty -Path HKCU:\Software\Microsoft\Office\15.0\Outlook\Options\General -Name DelegateWastebasketStyle -PropertyType DWORD -Value 4 -Force

You can change the path to fit your Outlook version.

Note : I may have to rebuild the Outlook profile and reboot the computer for those changes to be effective. You also need to configure Outlook in Exchange cache mode, otherwise, it does not work.

You may want to deploy this by GPO before your roll out.