Can OST file be converted to PST? If yes, then use of OST to PST Converter Tool. This tool helps all professional and non-professional users to export multiple OST file into Outlook PST format on any version of Windows OS including all emails, notes, tasks, contacts, calendars, and attachments. The OST to PST Tool can bulk export OST file into Outlook in a single procedure without any problem. To know more about the software and its working, you should first use its Free Demo Version, which is supportable to import first 25 emails from every OST file to PST without cost.