When you are transferring data from Outlook OST file to PST file format then you need software to make this possible. So I suggest you OST to PST Converter tool that has the best features to convert data from OST file to PST file format. Apart from its support cloud-based application Office365 & Live Exchange Server. It backing all the version of MS Outlook such as 97, 98, 2000, 2002, 2003, 2007, 2010, 2013, 2016, and 2019. With the aid of this program, users migrate their data into several file formats such as PST, EML, EMLX, MBOX, HTML, vCal, vCard, and MSG.