If you are still searching for OST to PST converting tool for migrating the OST file into PST file format, then you can go with the MailsDaddy OST to PST Converter tool. Because
1. It provides multiple file migration at once.
2:- Export OST to PST, EML, MSG, MBOX, contact in CSV and calendar in ICS format
3. Conversion result does not vary from the actual. 
4:- Helps to view the preview of overall PST file databases.
5. Migration can be also done into Live Exchange Server and Office 365.
6. It converts all data fully not partially.
7:- Can be installed on overall Windows systems.

For more information, visit here:- https://www.mailsdaddy.com/ost-to-pst-converter/