Short description of Unistal OST to PST Converter 12.0: Unistal OST to PST Converter Software successfully convert OST file to PST file at the time when Exchange server goes down. Unistal OST Recovery tool only convert healthy OST files. Exchange OST Recovery Software easily convert ost files with all of its items like emails, calendar, notes, tasks, contacts, attachments. OST to PST converter easily transfer all emails with there properties to PST. Software convert password protected OST file.