I have a surprise for you I found the best software for opening the OST file in Outlook. Try Enstella OST to PST converter software for your problems. This software has multiple formats like OST to PST, EML, MSG, HTML, MBOX, VCARD, EMLX, and other formats and many mailbox items components, emails, attachments, contacts, calendars, etc. MS Outlook versions software can read OST 202, 2019, 2016, 2013, 2010, 2007, and 2003 all previous editions of MS Outlook.