Remove Duplicate Contacts is a powerful and easy-to-use Microsoft Outlook Add-In for searching and processing of duplicate contacts in Microsoft Outlook folders.

Features
High-speed searching and processing (delete, copy, move).
More than one Million contact items supported.
Compare attachments and attached files of all contact copies.
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.

You can use the add-in for Outlook to find contact copies both in a single folder and in different folders.
A duplicate contact item found can be:

Deleted
Copied to any folder you choose
Moved to any folder you choose

Latest version: 4.0
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

There are two different work modes in Remove Duplicate Contacts:

Search for duplicate contacts in each individual folder

In this mode, the program processes each selected folder separately, with no relation to other folders. Two identical contacts are deemed duplicates provided they are stored in the same folder.

The work mode is designed to search for duplicate contacts stored in the same folder. It will help you to get rid of unneeded contact copies in one or several folders.

Search for duplicate contacts across a group of folders according to their priority

When this mode is chosen, the program will search for duplicates of a contact item not only in the same folder, but also in all other folders you selected.

If some identical contacts are stored in different folders, the contact stored in the high-priority level folder you choose, as "Important Contacts", will be left intact, the others will be processed (deleted, copied, moved).