Best Yahoo Backup Tool – Securely Save and Protect Your Emails Offline Backing up Yahoo emails is essential to avoid unexpected data loss, accidental deletions, or server downtime. The Yahoo Backup Tool provides a seamless solution to securely download and save Yahoo mailbox items into different formats like PST, MBOX, EML, MSG, and more. With advanced compatibility, it works efficiently as an MBOX to PST Converter, OST to PST Converter, and EML to PST Converter, giving you complete flexibility for data migration and backup.