Are you still searching for a perfect and safe solution to convert OST files into Outlook PST format? I would suggest you to use the well-known and advanced solution for the conversion. You can use the smart OST to PST converter which allows users to save OST mailbox items in PST, EML, MSG, MBOX, etc. There is also a free version available for evaluating the performance of the utility. in this way no data is shared with any third person. You can download this software from here:-https://www.betavare.com/ost/pst/
ost to pst converter full version tool to convert data from single, multiple OST files in new Outlook PS file. Free unlimited ost to pst converter online tool can conversion multiple mailboxes that contain inbox, outbox, sent-items, deleted-items, drafts, notes (to, cc, bcc, subject, date, and time) into pst Outlook format. By using OST file converter tool to ost to pst outlook, office 365, PST, Live Exchange server, Gmail, OLM, NSF, EMLX, vCal, vCard, EML, MSG, HTML, Zimbra, PDF, MBOX, and etc.