User is compatible to use the wonderful software to perfectly move KDETools PST to MBOX file so I suggest you choose effective software MBOX to PST to MBOX Converter. This is a flawless solution that helps many users to convert and import PST data to MBOX format. The software can convert PST files to Office 365 and exchange servers. There is no file size limit for converting PST to MBOX. It can import PST files into Outlook 2019, 2016, 2013, 2010, 2007, 2003 etc.
VISIT HERE:
https://www.kdetools.com/pst/mbox/