Last reviewed on November 7, 2014   —  19 comments

While you can remove duplicates by hand, these tools make it easier when there are a lot of duplicates.

The following pages are a collection of mail utilities for Microsoft Outlook that don’t fit any of the categories listed under More Information.

There is a separate page for each type of utility and those who don’t fit within the four main types of utilities are under Mail Tools for Outlook.

This page lists duplicate remover tools. Although some of these tools work only with the mail folders, many will work on any Outlook folder that contains duplicates.

Manually Remove Duplicates Outlook 2003 and up | | Duplicate Remover Tools

Manually Remove Duplicates from Outlook 2003 and up

To remove duplicates, you need to use a single line table view.

In an email folder using the default group view, click on the row of field names and deselect Show in Groups, then turn off the Reading pane or slide it to the right.

For email folders, all standard views use a table view and you just need to turn off grouping and move (or turn off) the reading pane to enable the single line view. In the calendar, choose Events or By Category view, or in Outlook 2010, the List view.

Single line list view in Outlook

With a single line view:
Choose the modified date in the field chooser dialog

  1. Right-click any column heading, then choose Field Chooser.
  2. In the Field Chooser, switch from the Frequently-used fields list to Date/Time fields, and then drag the Modified date field to the view to add it to the fields displayed.
  3. Click on the Modified column header to sort by that field.
  4. You should now see your Outlook items in reverse chronological order.
  5. Click on the first item you want to delete.
  6. Use the scroll bar to find the last item with the same modified date.
  7. Hold down the Shift key as you click on the last one. This selects all the items between the two selections.
  8. Press Delete to remove them all from the folder.
  9. Reset the view when finished.

This method works well with imported items or when you re-download messages left on the email server because you’ll have one set of items with the same modified date.

To remove duplicate holidays from the Calendar folder in Microsoft Outlook
How to remove duplicate imported items in Outlook (Microsoft KB Article)

Deleted Duplicated Email Video Tutorial

The steps for Outlook 2003 and up are basically the same, except for the menu commands to turn the reading pane off and on. The first half of the video was recorded in Outlook 2010, the second half in Outlook 2007.

To turn the reading pane off and on in Outlook 2010, go to the View ribbon and expand the Reading pane menu.

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 Email Remover

Finds and removes duplicates, even if the messages appear in different folders. Delete, move, or copy duplicates to any folder. Mark duplicate messages with a flag. Search for duplicates in the same folder, or in different ones. Process duplicates in Public folders on the Exchange Server.

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.

E-mail Duplicates Eliminator

Cleans up a single folder by either deleting duplicates or moving them to a separate folder. Duplicate Email Eliminator Across Folders is a version to find duplicates across multiple folders. Enter code WD9BHK53 during checkout.


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.

Delete Duplicate Email

When you reuse an old .pst file with a POP3 account or synchronize with smartphones/PDAs, you can inadvertently create duplicate messages. With the Delete Duplicate Email add-in, you can quickly delete these duplicate messages with just one click of a button! Works with Outlook 2000-2013 32 and 64-bit and Windows 8.

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 Notes Eliminator

Clean up your Notes folder, especially if synchronizing with your PDA leaves a lot of duplicates. For Outlook 2000 and 2002. Enter code WD9BHK53 during checkout.

Duplicate Posts Eliminator

Clean your Outlook folders of post items. Supports mailbox, PST, and Exchange public folders. Supports Outlook 2010 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.

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.

ReliefJet Essentials for Outlook

The updated version of ReliefJet Essentials for Outlook adds many new features including support for Quick Text with hotkeys and expandable macros. New utilities added like Add BCC to Messages and Redirect Messages. All utilities can be integrated with Outlook Rules. A command line tool for Outlook professionals and administrators is also provided. More than 70 tools and utilities are now included. New utilities and features as well as performance enhancements. Improved compatibility with Outlook 2013, Office 365 and Windows 8.1.


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

Stellar Outlook Manager

With Stellar Outlook Manager you can back-up your important emails, compact large PST file, identify and remove duplicate emails, get back lost password, repair corrupt PST files and even split large PST files. All these functions can be managed conveniently in just a few clicks through a central console.

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.

Next page >> Outlook 2002 and older


  1. Tom says

    Thanks so much. I nuked my machine and did a clean install. As I don't delete mail from the server I had over 7,000 messages duplicated. This saved me a lot of time and money :)

  2. Jorge Ferreira says

    beatiful solution!
    simple, basic and smart!
    thank you very much! I finally be able to delete my triplicated emails.

  3. David says

    Sorry, but I don't see how sorting by modified date allows me to make any distinction on whether an email is a duplicate.

    • Diane Poremsky says

      The Modified date field shows you when the message was downloaded or imported. When you have duplicated messages they were imported or downloaded at different times than the original copy of the message. With the modified date in the view you can sort by subject and compare the modified dates then sort by modified date so it's easier to select a large number of duplicated messages at once. (hold shift as you select the first duplicated and last duplicated messages)

  4. Larry says

    I found the "office duplicates remover" free version just an excellent product with easy installation on Windows 7 64-bit even though it was a 32-bit 2003 version. It worked just fabulous and would recommend.

  5. Geoff says

    With Outlook 2010, I created an "Unread Mail" folder under my "Search Folders". It compiles all unread messages into one place and you can just highlight and delete. This is good assuming you read all of your mail prior to getting the "dump" of dupes. if you don't, then maybe this other method will suit you better. I just like having it as a permanent addition and not needing to switch my views back and forth. I have to deal with this every few months.

    • Diane Poremsky says

      The Outlook Duplicates Remover which is 3rd from the bottom is free. That is the only one that is free AFAIK.

  6. Federico says

    Duplicate Remover or Duplicate Killer from 4Team doesn't work if the duplicates have identical content with even small formal difference. For instance I have for some reasons double items in sent folder. The only difference is that in one the email address names are written [Name Last name <] in the other one ['Name Last name' <]. So just a \' difference. The software is not able to understand that the two emails are identical. I spent money for nothing.

    • Diane Poremsky says

      To be fair, I don't think I'd want a duplicate remover that looked at two similar contacts and decided they were duplicates. They could delete the "wrong" contact, keeping the contact you didn't want and removing the one you wanted to keep - is "O'Toole, Mary emailaddress" the one they should keep, or "OToole, Mary emailaddress"?

  7. Jeffrey Dolberg says

    I'm looking for a different type of Duplicate Remover; one that removes notes that are contained in other notes.That is, if you send me an email, and I respond to you, then you respond to me, I have 3 different emails, but all I need is the last one because it contains the information from the previous 2. How can I accomplish this? This will require searching both Inbox and Sent Items.

    • Diane Poremsky says

      What version of Outlook? 2010 and 2013 have a clean up conversation feature which does this. There are one or two addins that can do this too - should be somewhere in the long list of tools here, but i forget the names offhand. :( If you aren't using Outlook 2010/2013, I'll see if i can find them.

  8. Jeffrey Dolberg says

    Thanks Diane. I'm using Outlook 2007. I found a tool called DupeDuster from Ivitar Software about 12 years ago. I have been using it ever since but it does not handle attachments correctly and often gets confused if an embedded note came from a source other than Outlook. If you know of something else I would be grateful to hear about it.

  9. Erik Jan says

    A few years ago I asked the developer from "Delete Duplicates for Outlook" to add that to the features of his program. He did, it's called "Special Comparison". There's a lot to tweak to make it work and I'm having some problems in the latest versions but in principle it should work.

  10. Victor Delta says

    I have an Outlook 2003 folder which often accumulates duplicate emails (usually pairs - don't ask, it's a long story!). Rather than delete them automatically, I am looking for a macro which will highlight one of each pair in the folder. Does anyone know if such a thing exists please?

    • Diane PoremskyDiane Poremsky says

      I don't have any macros that do this, but it should be easy enough to do, I'd compare the subject and sender of two messages and set a category on one if a match is found, then move to the next message.

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