The best way to change PST to MBOX with attachments is to use an efficient and reliable tool like OSTtoPSTAPP Outlook PST Converter Software. This utility smoothly converts PST files to MBOX format or many other different file formats (EML, MSG, etc.) with attachments. This application easily converts any size of Outlook PST files without any restriction. Also, this tool is useful for both technical and non-technical users and this application supports both ANSI and UNICODE MS Outlook PST files. Also, this tool supports all versions of the Windows Operating System (11, 10, and older versions).