Here is a simple way where you can Convert OST to PST file format in just couple of clicks.
With the help of this OST to PST Converter Software you can Convert your OST file into PST, EML, MSG, MBOX, HTML, ICS, VCARD formats.
It allows user to Convert OST to PST in safe manner and you can also recover your all deleted OST files including notes, contacts, tasks, emails, journals, notes, and more.
You can also try free demo version of this tool.