You can remove duplicate PST files. I suggest the SameTools PST Duplicate Remover tool. The tool scans the PST files and removes the duplicate items in a few clicks. The tool will delete multiple duplicate PST files like emails, notes, tasks, contects, etc with in one clicks. You do not need to install any other tool. It is available on all versions of Windows operating systems Windows 11, 10, 8.1, 8, and 7. The user interface and simplicity of the tool are intended for everyone, even for someone who has little technical knowledge. Use a free trial before buying this tool.
Visit here: https://www.sametools.com/duplicate/pst/