If you're having trouble converting the Outlook OST database to PST format, you'll need a professional application like
OST to PST Converter Tool to convert the OST emails to PST files along with all attachments. It also save converted OST file to EML, MSG, HTML, PDF, and MBOX.
This software can restore and recover your corrupted .ost files info, such as emails, contacts, calendars, tasks, notes, and dates, as well as deleted emails. In just a few clicks, this software can export OST file to Office365 and live Exchange Server. It GUI is very simple and user friendly. It provide free trial version that ensure the users about its features and functions.