Try inexpensive and safe software. The software is KDETools PST to MBOX Converter, which allows users to convert multiple files. With this software, data can be saved and imported into various file formats like EML, EMLX, MSG, HTML etc. There are no file size restrictions as the software can import any file size without errors. The PST converter is compatible with all versions of Windows and MS Outlook.
Click here: https://www.kdetools.com/pst/mbox/