eSoftTools OST to PST Converter software is best to export OST file to PST without the need of Outlook. It recovers data from inaccessible OST file and it also exports/saves OST data to PST, MBOX, Yahoo, Gmail, Office 365, Zimbra TGZ, HTML, vCard and many other options. This program supports all Windows version O/S. You can also try this tool with demo edition which can allow you to convert OST for free. Read more- https://www.esofttools.com/ost-to-pst-converter.html