Yes, there are many ways to remove duplicate MBOX files without deleting the original MBOX files. I recommend the best tool, as I use it myself. You can use SameTools MBOX Duplicate Remover, which quickly scans your MBOX files including emails and attachments, finds the duplicate items and removes them without affecting your original data. The software handles a large number of duplicate MBOX items without requiring any other tool. The tool has a simple interface best for users without technical expertise who will find it easy to use. It is compatible with all versions of Windows including 11, 10, 8.1, 8, and 7. The application offers a free demo version before purchase. After removing the duplicate items from MBOX it displays a preview of the results.
Visit here:
http://www.sametools.com/duplicate/mbox/