Remove All Duplicates is a powerful and easy-to-use Microsoft Outlook Add-In for searching and deleting duplicates in Microsoft Outlook folders and mailboxes, including Emails, Contacts, Tasks, Notes, Journal Items and Calendar Items (Appointments). Remove All Duplicates includes the following addins: Remove Duplicate Emails for Outlook Remove Duplicate Contacts for Outlook Remove Duplicate Journals for Outlook Remove Duplicate Tasks for Outlook Remove Duplicate Notes for Outlook Remove Duplicate Calendar (Appointments) for Outlook Features High-speed searching and processing (delete, mark, copy, move). More than one Million items supported. Compare attachments and attached files. Multiple formats of an email message or post are compatibled, including HTML, RTF, plain TEXT and more. Easy to change the option: Work for all users on this computer, or only work for the current user. Easy to enable or disable this addin. Latest version: 4.0.1 Operating System: Windows 2000, Windows XP, Windows 2003, Windows Vista, Windows 2008, Windows 7 Microsoft Office Outlook 2007 and Outlook 2003 Business Contact Manager 2007 and 2003 Supported Remove All Duplicates can be used to find Outlook item copies both in one folder and in different folders. A duplicate Outlook item found can be marked, deleted, copied or moved to any folder you choose. There are two different work modes in Remove All Duplicates: Search for duplicate item copies in each individual folder Search for duplicate item copies across a group of folders according to their priority High-speed searching and processing (delete, mark, copy, move). More than one Million email messages and posts supported. Compare attachments and attached files of all email copies. Multiple formats of an email message or post are compatibled, including HTML, RTF, plain TEXT and more.
Source: http://www.accmsoft.com/office-outlook/remove-all-duplicates/