The most recommended tool is eSoftTools OST to NSF Converter tool. It can support all Windows and MS Outlook versions like XP, 7, 8, 10. And 2003, 2007, 2010, 2013, 2016.This tool migrates all email data like inbox, sent items, draft, notes, journal, task, appointments, calendar, contacts etc into NSF format. If you have multiple files of OST and want to convert selective OST files, you can easily convert OST to NSF format. It’s 100% safe and secure software.