Use this ToolsGround OST to PST converter
software for recovering and converting OST file to PST file. With the help of this OST file conversion, all users can import OST to PST, EML, MSG, ICS, vCard, HTML, MHTML and MBOX File. The program can import OST into PST including all emails, contacts, calendar, tasks, notes, journals, and all attachments, etc.
More Info;- https://www.toolsground.com/ost-to-pst-converter/