You can use Vartika Zimbra to PST Converter. It is the safe and secure tool which can efficiently convert Zimbra file to MBOX and other file formats like PST, EML, EMLX, HTML, PDF, MSG, etc… If the user has a larger file size, the partition option is also helpful. It works MS Outlook all versions like -2000, 2002, 2003, 2008, 2010, 2013, 2016, and latest 2019.

Know more info-https://www.vartikasoftware.com/product/zimbra-to-pst-converter.html#