If you want to import outlook OST file into PST file. I suggest to you the best solution: eSoftTools OST to PST Converter tool. It can recover all email items, drafts, sent items, appointments, notes, journals, tasks with all email properties like to, cc, bcc, subject, etc. it can also convert OST files into multiple formats such as PST, EML, EMLX, Gmail, Office 365, vCard, MBOX, MSG, HTML, etc. it’s based on a GUI window which can make it easiest to use. Users can download a free demo file to convert OST files

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