You can try profitable solution like KDETools Zimbra to Outlook Converter Tool is the most great tool for import Zimbra to Outlook PST. Some additional features are:

• Zimbra converter import Zimbra TGZ file to PST other file formats like OLM, NSF, MBOX, PDF, EML, EMLX, HTML, etc.
• This software does not make any changes while migrating.
• This software directly import Zimbra file to Office 365 and Exchange Server account.
• This tool has Fast conversion of data without losing any data.
• This software shows a free preview of the data before the conversion process.
• This software works on all versions of Windows, including 7, 8, 8.1, XP, and 10.
Read More: https://www.kdetools.com/zimbra/