Try CubexSoft PST to MBOX Converter - a perfect and reliable solution to convert multiple Outlook PST files to MBOX file format with complete emails, formatting, and attachments without Outlook. It has a very simple GUI, both technical and non-technical users can easily handle and manage the software without any help. This software supports all MBOX based email clients like Thunderbird, Apple Mail, Eudora, Entourage, and many more. It was compatible with both Mac OS and Windows OS including Windows 11.