I want to recommend you eSoftTools OST to PST Converter software to convert Outlook OST files. It easily recovers damaged and corrupted Outlook OST file and give you accurate results. This tool allows converting Outlook OST file into pSt ad various formats such as EML, HTML, Yahoo, Gmail, Office 365, MBOX, EMLX, Zimbra, MSG, vCard, and ICS. It also provides a money-back guarantee and technical support. Check the free demo version of this tool and get 25 mailbox items from each folder.

Read more- Convert Outlook OST files