I ran into the same issue when someone shared an MBOX archive, but I didn’t have Thunderbird installed. Instead of setting up a full email client, I used MacSonik MBOX Viewer. It allowed me to open and read the emails directly from the MBOX file. The tool shows email content, attachments, and folder structure without requiring any email account configuration. This utility is well equipped with features like viewing large files, previewing files, and viewing attachments without any issue. This tool is compatible with all versions of Windows OS.