I am here to suggest one of the best software for converting OST to PST files, try this OST to PST converter software(Datarepairttols) for converting multiple OST files to PST files. This software has many mailbox items like many mailbox items contacts, attachments, embedded images, journals, tasks, calendars, distribution lists, draft folders, etc, and exports OST files to Office365, Gmail, Yahoo Mail, and Outlook.com webmail. This software gives a free demo version for all users and converts 25 items of every folder & subfolder. MS Outlook is not required for this software.