Yes, it is possible to remove duplicates from PST without risking the original data. I can suggest the best tool becouse I'm also using so you can try it. Try the TrustVare Outlook Duplicate Remover, which quickly scans Outlook files and finds duplicate items and removes them wihtout losing original data. There is no need to download any application to operate it. The software manages a large number of duplicate PST files without facing any issues. It has a simple interface that allows non-technical users to use it without technical skills. You don't buy their full edition, first try the free trial, see their removal process, then buy it.