---
title: "Microsoft Exchange - Error -3407 (unknown) during Mailbox backup"
slug: "microsoft-exchange-error-3407-unknown-during-mailbox-backup"
updated: 2023-11-07T22:31:28Z
published: 2023-11-07T22:32:19Z
canonical: "docs.retrospect.com/microsoft-exchange-error-3407-unknown-during-mailbox-backup"
---

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# Microsoft Exchange - Error -3407 (unknown) during Mailbox backup

Microsoft Exchange and SQL

Removing that mailbox from the script is typically the simplest approach to resolving this error.

If this is still an active mailbox, then Retrospect may have having trouble accessing it. Try removing the mailbox from Retrospect and adding it again.

Last Update: February 13, 2012