If you are searching for the best OST file conversion tool so I suggest you PassFixer OST to PST Converter software is tool is really very cool and advanced. You can easily convert Outlook OST file into PST and many other formats such as EML, HTML, Yahoo, Gmail, Office 365, EMLX, MSG, ICS, MBOX, vCard, and Zimbra. download the free demo version of this tool from the official website of PassFixer.
Read more- Convert Outlook OST file into PST
if you search any ost to pst converter software and not find any ost to pst converter software try stella ost to pst converter software to convert all ost mailbox items in to pst file this software is convert all 32bit and 64bit ost file this software is convert all ost mailbox items using some simple steps. This software is convert all corrupted and unmounted ost mailbox items in to pst file. for more info visit this link https://www.stelladatarecovery.com/ost-to-pst-converter.html