The solution which is most recommending by experts that named is ATS OST to PST Converter Software. It does not need MS Outlook installation for OST file to PST file conversion tasks. It export all the information from Outlook OST including notes, tasks, contacts, emails, journal items, sent items, journals and more into PST file formats without any hassle. This converter software is supportable with all the editions of MS Outlook and OS Windows. Additionally, you can export your OST data files into PST, HTML, EML, EMLX, Office365, MSG, MBOX, and many more.