Last reviewed on April 30, 2015   —  2 Comments

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This is a collection of tools used to remove duplicates from your Microsoft Outlook Contacts folder. Some of these tools will also remove duplicates from other Outlook folders.

When the duplicates are the result of importing and all are duplicated, you can sort by the modified date field (you’ll need to add the Modified field to the view), then delete all of the items with the same modified date and time. When the duplicates have assorted modified times, you’ll need to delete the duplicates yourself or use one of the many duplicate remover tools to automate the process.

Warning: Deleting duplicates in an account synced using Exchange Active Sync (EAS) can result in lost contacts. Export to a backup file first.

  1. If not using a list view, switch to a list view.
  2. Right click on the row of field names
  3. Choose Field Chooser
  4. Find the Modified field in one of the All <type> fields list.
  5. Drag the field to the row of field names and drop
  6. Sort by the Modified field.

Sort by the modified date field

Some tools, such as Outlook Contacts Scrubber, will merge the data on duplicate contacts to one contact. This is useful if you are combining contact lists from different computers and the data on the contacts are not identical.


Tools in the Spotlight

Deduper - Outlook Duplicate Remover

Deduper does exactly as the name suggests, it searches and removes all duplicates - including appointments, contacts, notes, tasks or emails.

Duplicate Killer

Outlook duplicate remover add-in for Microsoft Outlook to find and remove duplicate contacts, emails, calendar items, tasks and notes automatically. Remove Outlook duplicates. Merge Outlook contacts and other items. Compare, assign category, flag and move duplicates to selected folders. Preview duplicate search results prior to processing. Duplicate Killer has Junk Contacts removal functionality, regarding contacts that have too little information. Duplicate Killer is compatible with the latest Windows 8 and Outlook 2013.

Duplicates Remover for Outlook

Delete duplicate contacts, notes, tasks, journal and calendar items in Microsoft Outlook folders and Exchange Server folders. Duplicates can be marked, copied or moved to any folder. It supports searching across the folders. Supports all versions of Outlook, including Outlook 2007/2010. Version 2.6


1-Click Duplicate Delete

1-click solution to remove duplicate mails, contacts or calendar items. Merges contacts automatically, has an undo function and a configurable advanced mode. Version 3.03 Now supports Outlook 2010 (both 32 and 64 bit).

Accurate Outlook Duplicate Remover

Accurate Outlook Duplicate Remover (AODR) can find and remove all duplicate Outlook items automatically. It quickly removes duplicates from Contacts, Calendar, Tasks, Notes and Email folders in one click. You can select any folder for duplicate Removing. It helps you to use your Outlook much more efficiently. Free.

Anti-Dupe for Microsoft Outlook

Remove unwanted Outlook duplicate records with Anti-Dupe for Microsoft Outlook add-in utility. Anti-Dupe for Outlook scans and deletes duplicate Outlook duplicate appointments, contacts, emails and tasks based on pre-determined criterion set by Anti-Dupe. Trial version available.

Contacts Scrubber

Free (up to 100 records) or Pro version (unlimited records) to clean up duplicate contacts. Lets you make field-by-field choices of which data you want to retain and drag and drop the data. Merges categories and other keywords fields. Supports custom forms. Works with Outlook 2003 to 2010. Version 4.

Delete Duplicate Contacts

Synchronizations with smartphones/PDAs inadvertently create duplicate contacts and you are left with a big mess on your hands. With the Delete Duplicate Contacts add-in, you can quickly delete these duplicate contacts with just one click of a button. Now compatible with Outlook 2000-2013, 32-bit and 64-bit!

Delete Duplicates for Outlook

Delete Duplicates for Outlook deletes duplicate e-mails. Detect and remove duplicate messages, contacts, calendar items, tasks, journal entries and notes. Compare messages by content (Standard), by part of the content (Special) or by unique message-id's (Light). Compare attachments and/or embedded files, by name and/or by content. Compare duplicates across several mailboxes or in within the boundaries of individual mailboxes. Use Regular Expressions. Works with all Outlook versions, inc. Outlook 2010/2013 32 or 64-bit.

Duplicate Contact Eliminator

Either delete duplicate contacts or move them to a separate folder. Enter code WD9BHK53 during checkout.

Kernel for Outlook Duplicates

Find the duplicates email items of Outlook Mailbox and easily remove, mark or flag them. You can also move duplicate items into subfolder and control on the unnecessary growth of pst file.

LBE Toolbox for MS Outlook

Multifunction utility to send individual messages to a list generated either from a text file or from criteria on the Contacts folder, remove large file attachments, remove duplicate contacts and messages, and perform a few other little chores.

NoMoreDupes for Outlook

NoMoreDupes detects and removes all duplicated Outlook items both in an Outlook pst file, a public folder or in an Exchange account. It shows the found duplicates in a preview for the user to decide which duplicates to remove. You can move the duplicated Outlook items to your "Deleted Items" or to any other folder you specify. NoMoreDupes uses a special algorithm to detect the Outlook duplicates. This Outlook-Add-In works with all versions of Outlook, including Outlook 2010/2013 64bit.

OL LookForDuplicates

Find & remove duplicates with this open-source VBA-Script. Searches for duplicate entries of any type (calendar, contact, e-mail, notes, task, etc.) across folders in Outlook. Suspected duplicates are listed and can be moved to the Deleted Items folder.

Outlook Duplicate Items Remover

Free tool for removing duplicate items from Outlook folders. ODIR recognizes duplicates in Contacts; Calendar; Tasks; Notes and Email folders. Using ODIR is very easy: select a folder and click the button Remove Duplicate Items. ODIR scans the selected folder for duplicates and MOVES all duplicates found to a subfolder ODIR_duplicate_items. Version 1.2

Outlook Duplicate Remover

Outlook Duplicate Remover allows you to find and remove Outlook duplicates and junk contacts in one click. Search duplicate items and merge Outlook duplicates automatically. Remove Outlook duplicates, such as duplicate Email, duplicate Contacts and Calendar events and Junk contacts. It is an automatic software add-in for Microsoft Outlook without any settings to configure. Duplicate Remover is compatible with latest Windows 8 and Outlook 2013 (including Outlook "Click-to-Run" versions) as well as Outlook 2010, 2007, 2003, 2002 and Exchange Server Public Folders. Supports French and German languages.

Outlook Duplicates Remover

Removes duplicate items from Calendar, Tasks, Contacts, Notes, and mail folders. Free.


Online service to eliminate wasted time by merging, cleaning, and eradicating contact conflicts. Works with Outlook, Gmail, Yahoo, and Mac address books.

Stellar Phoenix Duplicate Remover

Clean up your Outlook mailbox from unwanted and duplicate emails with Outlook duplicate remover tool. This software works as an Add-Ins in Outlook and removes duplicates as per different time span and scan criteria. Customized operations like Mark as Expired or Flag, Delete Permanently, Copy to folder and more are also a notable feature of this software.


  1. Belinda says

    Oh dear, what have I done? Downloaded Cosi for ipad, and saved Outlook 2007 calendar as it said as a pst file, then downloaded the Cosi toolbar to sync. All worked well. But then noticed all outlook appointments had blue square on them. So deleted Cosi off ipad, emailed them re my deletion, then deleted via Control panel Programs. Then reinstalled according to Cosi's directions and now I have a new calendar and an old calendar mixed up with old recurring appointments coming up all the time. I don't know how to remove them. I've tried deleting the old recurring appointments to no avail. Any ideas muchly appreciated?

    • Diane Poremsky says

      In Outlook... is every thing in one calendar folder or in two? Normally, the best way to delete stuff from the calendar is using a list view but I'm not clear if the problem is in your default calendar in Outlook or with the sync process as I'm not real familar with the cozi app.

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