For OST to PST Conversion you can use this Regain OST to PST Converter tool that can Convert OST to PST easily. this software also able to Export OST emails to many other file formats like: PST, EML, MSG, MBOX, HTML, ICS, VCARD formats and Office 365 Account or Live Exchange Server. This tool smoothly extracts all the data in OST files and stores them securely in new PST file. user can easily see the preview of all emails items like emails, attachments, contacts, notes, calender and journals etc. before the conversion.