If you are looking for the best conversion tool, so we suggest the best third-party tool that is
ATS Outlook OST Recovery Tool. It has many features that make the conversion process smooth and reliable.
To store your data you can export them into PST, EML, HTML, EMLX, MSG, vCal, vCard, and MBOX file format. The users can also export the data into Cloud-based application Office365 & live Exchange Server that is an additional feature of this program.
The application is designed with the best algorithm and the best technology. It not make any changes in the database while you export the data from Exchange OST file to Outlook PST file format. The application give preview facility in which you can see the preview of the recovered mailbox along with email, notes, contact, attachment, task and many more.

To use this application, you need to go at our Official site. If you want to see the working performance before purchasing it, then you need to download the free demo version. If you are happy with the demonstration, then purchase it without any delay.
Free Download Software with Softonic: https://ats-ost-to-pst-converter-toolkit.en.softonic.com/Free Download Software with Cnet: http://download.cnet.com/OST-to-PST-Converter/3000-2369_4-77530261.html