you can try this eSoftTools export OST to PST software. It has an amazing feature to convert OST files into PST without losing internal data. It provides multiple formats to convert OST files like PST, EML, EMLX, MSG, MBOX, OFFICE 365, HTML, MSG, etc. during the conversion this tool provides a live preview of the process of all mailbox folders.
Read More:- Best Free Outlook OST Converter