You can go with another popular high-ranked tool to convert OST to PST format which is MailsDaddy OST to PST Converter. It supports all newer and older versions of Outlook to perform OST to PST conversion. The tool has multiple conversion options to save Outlook emails in PST, MSG, EML, MBOX, HTML, Office 365 and Live Exchange Server. Recovery of email information from unhealthy OST files is also possible. There is no size limitation and users can export multiple OST files to PST or other required formats in a single duration.