The most reliable and best method to convert OST file to PST format with or without Outlook in your computer then I would recommend to use EmailsGuru OST to PST Converter . It is designed to convert OST file to PST format, preserving all email data, including attachments and folder structures during the conversion process. Moreover, it helps to recover corrupted or damaged OST file. It is developed with an advanced and modern algorithm, which makes it safe and best way to convert OST file to PST. It is fully compatible with all versions of Outlook and Windows OS, offering seamless compatibility. Users can also a free trial version of this well developed utility.