To convert MBOX files to Outlook PST, utilize the WholeClear MBOX to PST Converter Tool. It is a lightweight and simple-to-install program. This powerful tool has multiple functions that ensure a seamless and error-free conversion of MBOX files to Outlook PST format. Many email apps are supported, including Eudora, SeaMonkey, Thunderbird, PocoMail, Opera Mail, and Apple Mail. You may also test this program using the free trial version.

Process for exporting MBOX files as PST format -

Download, install, and launch the WholeClear MBOX to PST Converter on the Windows system.
Select the MBOX file you want to include and then click the "Next" button to proceed.
Use the Browse icon to add MBOX files and select file or folder mode.
Select the PST file format from the drop-down list in the subsequent window.
Select the location where the newly generated file should be saved and select the "Convert" icon to commence the conversion.