Try ZOOK OST to PST Converter is the prominent solution for users to export OST to PST format by maintaining the email properties and maintaining the folder structure of OST file.It provides the complete conversion of OST files into PST format by maintaining the data integrity and email attributes. At the end, users will get their complete emails at same folders and sub-folders without altering any information. It can be easily handled by any non-technical user to perform the migration process in few seconds. The application is designed by using the robust algorithms which has so much easy to use interface. The intuitive interface of the application can be easily understandable for users to perform the conversion process. The tool can easily support to the latest version of Outlook 2016 and all the below versions of Outlook for both 32-bit and 64-bit Windows operating system. In the demo edition, users can perform the conversion of 25 items from each folder of OST files into PST format.

Explore More:-  https://www.zooksoftware.com/ost-to-pst/

I want to suggest the OST to PST Converter application, which converts OST to Outlook PST with ease. This software works with all versions of MS Outlook and stores data in an offline folder so you may view it without having to connect to the internet. The file size has no significance on the quality of the conversion. You may get a free trial version that converts only a few items from each folder.
Visit: https://www.arysontechnologies.com/convert-ost-to-pst-online.html

There are lots of outlook PST converter are available on the Internet. But here I would like to suggest a tool which I use personally. It has been suggested by many users & experts. GUI of this tool is user-friendly & easy to use. It keeps the data safe & secure. You can even try the free version of this tool. Link is here: https://www.shdatarescue.com/pst-converter/