I have tried deleting duplicates in PST files but it is very frustrating to manually erase since I usually have a ton of data stored in my PST files. But I have heard about software that help with this problem. I found a tool online called Outlook duplicate remover. This tool removes Outlook PST'S duplicate items in no time. It saves your time and effort with no data loss. There are trial versions of this tool, you must try.
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