I recently received an OST file from my old Outlook account, and I need to convert it to MBOX format so that I can use it with Thunderbird and other email clients that support MBOX. I want to ensure that all my emails, attachments, and folder structure remain intact during the conversion. Can anyone suggest a reliable method or tool to convert OST to MBOX without data loss? Are there any free solutions, or do I need to use a professional converter? Also, please mention the steps to do it safely.