How to Remove Duplicate Items in Outlook For Free

If you are looking for ways to delete duplicate emails in Outlook then you have come to the right place. Here we will not only discuss the methods to remove duplicate items in Outlook but also check about its causes and they can affect the Outlook application. Duplicate entries in Outlook could come in any form, like the same name but different e-mail addresses, or when importing the data without checking the duplicate fields.

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When multiple items of the same type, name are added it becomes difficult for Outlook to recognize it and it takes a lot of time to give the correct results and thus degrading its performance. If you are looking for the best methods to delete duplicate items from Outlook 2016/ 2013/ 2010 and the previous version then this article will help as we discuss all the possible methods. But first, check what duplicate emails occur in Outlook.

Causes of Outlook Duplicate Items

Repeated Synchronization: While adding the same Outlook e-mail account on multiple devices could result in duplication of emails. Like on mobile and laptop this will cause repeated synchronization of incoming messages.

Incorrect Rules Configuration in Outlook: If the Outlook sending and receiving emails is not set up properly it creates a problem with the items and causes duplicates in Outlook

Mailbox Settings: When the mailbox parameters are not set up properly while creating an Outlook account the new items will add up to old items having the same entry resulting in Outlook duplicates

Short Intervals in Sending and Receiving Emails: If the messages are sent and received at a faster rate the inbox doesn’t get synchronized and creates duplicate items.

Conversion from Other Email Application: When moving items from other email clients which is already link with Outlook account creates duplicate emails, contacts, attachments in Outlook

Why is it Necessary to Delete Duplicate Emails in Outlook

  • Duplicate entries create several issues in Outlook like
  • As more items are added to Outlook it increases the PST size and if it exceeds the Outlook PST size limit, the PST file becomes corrupt
  • When searching for a specific item the Outlook looks in entire files and as the size is large it takes more time to search
  • While sending and receiving the messages, the Outlook hangs or freezes

Top 5 Methods to Remove Outlook Duplicate Items

  1. Increase Outlook Inbox Update Frequency

  • Sign in to your Outlook account and click on Send/ Receive


  • Click on Define Send or Receive Groups
  • Now increase Outlook update frequency to 15-30 minutes

2. Use Outlook Clean-Up Method

  • Start Outlook and sign in to your account
  • Select the folder in which duplicate emails are present
  • Click on ‘Home Tab’ and then select CleanUp


  • There are three options select as per choice
    • Clean Up Conversation: To delete duplicate emails in the conversation
    • Clean Up Folder: To remove duplicate emails from any folder
    • Clean Up Folder and Sub-folders: To delete duplicate folders and subfolders
  • Also, delete the emails from ‘Delete Folder’ and ‘Empty Folder’

3. Check Outlook Rules

Open Outlook and check the Outlook rules, if there is any problem with Outlook items or they are conflicting with each other, then modify the rules and save changes.

4. Change Server Connection and Anti-virus Settings

Outlook when connected online synchronizes with Exchange Server, the data is synchronized with OST files, and emails from the server are downloaded to the local PST file. Amid this process, the server policies and Anti-virus checks email for any viruses. If the antivirus adds the emails that are already approved by the Outlook server it creates duplicates. To change the email protection settings from Antivirus.

5. Kernel Outlook Duplicate Remover

An easy solution to get rid of all duplicate emails in Outlook at once is ‘Kernel for Outlook Duplicate Remover’. A powerful tool that removes all duplicate emails, contacts, attachments, in a single click. It analyzes the Outlook PST file and collects all duplicate items, you can even search for duplicate items by specifying the date range

Download Kernel Outlook Duplicate Remover

How to Use Kernel For Outlook Duplicate Remover

  • Start the Kernel for Outlook Duplicate Remover application
  • Click on the Add Task button a pop-up window will appear to create a new task click on Yes

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  • Enter the name of the task, description of what task is about and proceed next

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  • Now, your Outlook folders will open in the software, select folders that have duplicate items and click on Up or down button to prioritize folders having a large number of duplicate items

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  • Click the option to specify what to do with duplicate items i.e. ‘delete permanently’, ‘Mark as Expire’, or ‘Move to Deleted Folders’

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  • Select other items to check for duplicity other than emails, you can select from attachment files, sender’s/ receiver’s name, date, and time to send.

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  • The tool will scan the folders for duplicate items and do the action as specified

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  • Click on Save report and finally press the ‘Finish’ button

So, these are the top 5 methods to remove duplicate items from Outlook. With Kernel for Outlook Duplicate remover, you can delete duplicate emails, attachments, contacts in Outlook 2016/ 2013/ 2010 easily.

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