I would like to suggest you can also try ZOOK OST to PST Converter is the most efficient solution to convert OST to PST format. In the free demo edition of the utility, users are capable to convert 25 items from each folder.
Highlighted Features of ZOOK OST to PST Converter
* Complete conversion of OST files into PST format along with attachments, emails, folders, etc.
* Users can batch export OST to PST format at once.
* Folder Hierarchical Structure will remain same during OST to PST conversion.
* Retains Same Email Formatting of OST Emails into PST File too.
* Provides Desired Saving Location to Save Resultant PST File.
* Fully Supportable to OST Files of all Outlook editions.
* Smoothly Works on Windows OS.
Download and use it Now: https://www.zooksoftware.com/ost-to-pst/