If you have any questions related to how to convert OST files to MBOX, then you can try eSoftTools OST to MBOX converter software. It converts OST files which created from Outlook.com, IMAP, Office365, and Exchange server with all mailbox items from OST files to MBOX EML, EMLX, HTML, Yahoo Mail, Gmail, Office365, PST, MSG, and more formats without any error. It recovers orphaned and deleted OST files without any damage to OST file data. Before buying the software, try the free demo version of the tool in which users can save 25 items from each folder of OST file to MBOX.