Does SecureMailMerge work with "Shared Mailboxes"?

Use SecureMailMerge with a shared mailbox, an address with no license of its own that licensed users can send from with Send As permission. Here is how.

Updated September 2026

✅ Send as a Shared Mailbox (via your personal mailbox)

First off: You can use SecureMailMerge to send as a Shared Mailbox (just as with any alias). Install the add-in on your own mailbox, then choose the shared address in the From field. Your administrator must grant you Send As permission for that address. All you need to do is:

• create a new email in your personal mailbox, then
• change the “From” address in the Email composer window to the Shared Mailbox address, and
• then create a campaign with SecureMailMerge.

(If you don’t see the From field, click the “Show From” button in the ribbon.)

But there is a drawback to this “Send As” approach: The email will be sent from the Shared Mailbox, but the sent message is saved in your own Sent Items folder. This is because the email is sent from your account, not the Shared Mailbox account. Recipients will see the sender as the shared mailbox and any replies will go to the Shared Mailbox.

❌ Send from Shared Mailbox directly

Support for Outlook add-ins in shared mailboxes is limited, and unfortunately, opening the add-in inside a shared mailbox is not supported because it would require installing the add-in for the shared mailbox (rather than for your own mailbox). This is not unique to SecureMailMerge; as far as we know, no other plugins can offer these features either. Microsoft is constantly making more functionality available, but as of writing (September 2026), there is no estimated date for when this use case will be supported.