Go with the solution that is mentioned here for OST to PST export tool with the help of the best OST to PST conversion software all MS Outlook users can even try the demo version of the application as well. Prominent features of the tool are it offers users the to import Single and Multiple OST files with the help of this OST to PST Migration tool. Helping this tool you can quickly transfer OST in PST, office 365 account, pst, vCard, vCal, Gmail, live Exchange sever, office 365, zimbra, MBOX, EML, EMLX, NSF, HTML, PDF, OLM, and etc.
OST to PST Converter software
https://www.kdetools.com/ost/