Enabling ‘save to sent items’ for a mailbox ensures that messages sent using send on behalf permissions are saved to the sent items folder of the mailbox (in addition to being saved to the sent items folder of the sender’s mailbox).
To configure save to sent items for send on behalf messages, do the following:
- Open up user properties, select the Mailbox tab, and click Mailbox Delegation.
- Select/de-select Save a copy of Send on Behalf messages to Sent Items.
- Click OK twice to apply the settings.