Use eSoftTools Outlook PST Recovery Software if you don't know how to import an Outlook PST file into Zimbra Desktop. The software can recover all data from PST files, including calendars, contacts, emails, tasks, notes, attachments, and other objects, and you can see a live preview of each Outlook item as it is updated by the software. The file types supported by this utility include MBOX, EML, EMLX, MSG, and HTML vCards. The free demo version is available to all users. In the trial edition, you can recover up to 25 emails from each folder.
For more information:- Import Outlook PST File to Zimbra Desktop