The SysInspire will convert and recover OST files, including emails, inboxes, sent objects, drafts, delete-items, attachments, calendars, notes, and tasks. You can restore the converted file using a variety of file formats, including PST, EML, MSG, MBOX, vCard, and so on. If necessary, you can break large PST files into smaller bits. You can also see the conversion process unfold until it is completed. This tool's free demo version will convert 25 emails from ost to pst format.