If you want to convert your PST file to the MBOX format without installing the Outlook app, then this is not possible manually. You must use Yota PST to MBOX Converter Wizard which enables you to export all PST emails at once to MBOX file format. It does not require the Outlook installation on the system to perform the operation.
Steps to Convert PST to MBOX without Outlook are;
- Run the Yota PST file to MBOX Converter and click Open.
- Now, add the Outlook PST file on the software panel.
- Next, click Export and select MBOX as a saving format.
- Lastly, choose a destination and hit on Save button.