how to convert OST file to PST format?

[norabarlow]

If the OST file still opens with the same Outlook profile, try Outlook's Import/Export option first and export mailbox data to PST. That is the simplest manual way. The problem starts when the OST file is orphaned, corrupted, or Outlook no longer connects to the old Exchange account. Outlook export will probably fail if so. In this situation, you can use WholeClear OST to PST Converter to scan the OST file, preview mailbox data and export to PST format. It also supports inaccessible OST file and works offline without dependency of Outlook, Exchange and MAPI. Basic flow is simple: add OST file, scan it, preview folders, choose PST and convert. Always keep a copy of the original OST before starting.