If you are worried about how to open OST file then I suggest you this eSoftTools OST to PST Converter Tool is the best tool to recover OST files such as attachments, tasks, notes, journals, contacts, content, chats, msgs, etc. the software supports all variants of MS Outlook including 2000, 2007, 2010, 2013, and 2019. This OST software can migrate OST files into multiple types like HTML, Zimbra, PST, ICS, Gmail, Office 365, Yahoo, and many more.
To Know More Here:- Free OST to PST Converter Tool
So here is the best solution to all your problems related to the OST file use Softaken OST to PST Converter software. The user can export mailbox from OST and other updated versions. This software is 100% free from any type of virus users will not see any unwanted ads after the installation of the software.