To export large OST files to PST quickly, the most effective approach is to use a reliable OST to PST converter instead of manual Outlook methods, which are slow and often fail with big files. A tool like Advik OST to PST Converter  is built to handle large OST files (even 50GB or more) using advanced processing that speeds up conversion without overloading the system. It safely converts all emails, attachments, contacts, and folders into a PST file while maintaining the original structure. You simply add the OST file, choose PST as the output, and start the process—making it a fast, secure, and hassle-free way to export large OST files.