Free OST to PST Converter. Convert OST to PST, even if files are inaccessible. Use OST2 to import and export OST and PST files, data from and to Microsoft Outlook, Exchange, Office 365, Outlook.com, Google and G Suite. You will be able to choose a specific OST or PST file or you can scan your computer and OST2 will find all OST and PST files.