You can
merge PST files without losing directories with the
GainTools Merge PST Tool. The software is meant to combine numerous Outlook PST files into one PST file while retaining the original folder structure. It safely merges emails, contacts, calendars and attachments without modifying or destroying any folders throughout the process. The application also handles big PST files and offers a seamless, corruption-free combining experience, making it a perfect tool for organizing Outlook data without losing critical organizational structures.