An oversized PST data can slow the outlook client and prone to corruption issue. A duplicate pst is also part of this corruption. To overcome this problem you tool take some step first you should use manual process to remove duplicate. If manual process doesn't work well then i would like to recommend you to use any third party software which are easily available on internet. But To remove duplicate items from Outlook email client application, I would specially recommend you to use this PST duplicate remover software that will definitely helps you lot.
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Outlook Duplicates Remover tool allows user to remove all kinds of duplicate items in PST file without any data loss. With this tool you are capable to removing all duplicate items in PST mailbox like emails, notes, tasks, attachments, calendars, journals and etc.
The duplicate remover fully capable of removing all duplicate items in PST mailbox like emails, notes, tasks, attachments, calendars, journals and etc. this software provide batch option. with this option all users can easily remove multiple duplicate of pst files such as emails, contacts, journals, tasks, notes, etc.
It comes with so many advanced and well developed features to add more accuracy in this software which provide lots of options. This software support all version of MS outlook version such as 2000, 2003, 2007, 2010, 2013, 2016 and 2019.Visit here:- https://exchangeserverstips.wordpress.com/2016/11/15/how-to-remove-duplicate-outlook-pst-files-manually/