Fix Outlook Keeps Creating Duplicate Contacts

Updated On - March 10, 2023 by Henry Bray |

Reading Time: 6 minutes

Microsoft Outlook is an efficient email program that also serves as an organizer. Among the most widely used email clients, Outlook stands out due to its versatility. Microsoft Outlook is a PIM (personal information management) that helps you keep track of your email, calendar, notes, tasks, and contacts. Items can be viewed and modified on numerous portable gadgets. However, if you use Outlook regularly, you may run into the problem of Outlook keeps creating duplicate contacts and other data.

Finding the root cause of duplicate items in the Outlook account is the only way to fix the problem and stop further occurrences permanently.

To de-duplicate in Outlook, you won’t have to delete old messages and manually compare the ones you have. Emails, events, contacts, tasks, notes, and journals can all be deleted from Outlook and other email clients with the help of dedicated duplicate-delete programs.

We’ll go through why Outlook keeps creating duplicate contacts and other objects and what you can do about it.

Causes of duplicates in Microsoft Outlook

  1. Problem with an Internet connection

This could be due to a slow Internet connection, a network issue, or an error generated by the mail server during the download process.

Outlook will keep creating duplicate contacts for the same emails in the future. If the server does not obtain confirmation that you have read the message, it will not know that you have read it. This issue causes Outlook to repeatedly send identical emails without ever receiving a confirmation that they were successfully sent.

  1. Corrupted message on the server

Even if the server has recovered, a synchronization failure can occur if there is an infected or malformed message. Since the send/receive operation was not confirmed, the server will resume the process beginning with this message and continuing until the procedure is complete.

You need to get in touch with your IT administrator and have them erase the tainted communication.

  1. Synchronization of Outlook desktop with mobile app

Make sure you’re running Outlook’s syncing app’s most recent version to prevent Outlook keeps creating duplicate contacts. Certain programs, or older versions of certain programs, cannot detect duplicate data. Separate pieces are made on a different device if synchronization with such an app fails. At the time of the next synchronization, they can be handled as brand-new entries.

  1. Synchronizing calendars

Your mobile device’s event sync could be at blame if Outlook’s calendar shows multiple entries.

This is because identical invitations can arrive simultaneously on the desktop computer (through Outlook) and the mobile device (via the calendar app). Because they were made in separate ways and never synchronized before, the calendars do not detect these events as duplicates.

  1. Duplicated holidays in Outlook

Outlook duplicates holidays when you define a holiday for a contact, such as a birthday or an anniversary.

This duplication occurs because the contact’s information is updated, breaking the link between the contact and the calendar event.

It’s also possible that importing holidays is to blame for calendar duplication:

Go to File, then navigate to Options, select calendar > Calendar option> Add holidays.


Instead of updating the Outlook calendar, this approach repeats the holidays already there.

How to prevent Outlook keeps creating duplicate contacts issue

Cleaning up your Outlook contacts will be well spent if you take a few more minutes to learn how to maintain an orderly list in the future. You may do this quickly and easily by activating Outlook’s built-in feature that detects and eliminates duplicate contacts. If you’re using Microsoft Outlook 2019 or 2010, here’s how to do it:

  • To add or edit your contacts, you need first navigate to the File menu, then Options, and finally Contacts.
  • Secondly, go to “Names and filing,” and then check Check for Duplicate Contacts When Saving New Contacts. 2

So simple, right? If a new contact you create has a similar name or email address to an existing contact, Outlook will now advise combining them.

How to Delete Duplicate Contacts in Outlook

Outlook’s duplicate contacts can be deleted in several ways. The best strategy to use will depend on how many duplicate contacts you have. The first technique involves removing each contact individually. When dealing with a small number of duplicate contacts, this strategy excels. However, more sophisticated options are required if you have many duplicate contacts.

1. Delete Unnecessary Contacts One by One

  • Launch Outlook and click the People tab at the program’s bottom. 3
  • To switch to the mobile mode, click “Phone view” under “Current View.” 4
  • The first step is to remove all of the extra contacts.
  • You can eliminate them by selecting the Delete option with a right-click.

This method works well for a manageable subset of contacts, and duplicates can be quickly identified in Outlook. But if you have a lot of contacts and Outlook keeps creating duplicate contacts of them, you should use the following procedure.

2. Filter Contacts While Importing

This method entails exporting your contacts, then importing them into Outlook while filtering out any duplicate contacts.

Step 1: Export Contacts from Outlook

  • Open up Outlook, and then select the People tab.
  • Choose the New folder option from the context menu when you right-click the Contacts folder. 5
  • Select OK after you’ve given the folder a suitable name. 6
  • Then, copy all of your contacts into this fresh directory.
  • Select Open & Export from the File menu’s current drop-down.
  • Select the File Transfer button.
  • After making your selection, click the Next button.
  • To export your data as a .csv File, select that option and click Next once more.
  • Select the Contacts folder that was just made and continue with the wizard.
  • To go to the next step, select the desired location and click Next.
  • If you’re done, click the Finish button.

Step 2: Import Contacts to Outlook

  • Open Outlook and go to the File option from the ribbon bar.
  • In the Open & Export menu, click the Import/Export button.
  • Go to File > Import from another program or File and click Next.
  • Select the Comma Separated Value option, and then click Next.
  • Select the option to “not import duplicate items” and proceed.
  • To complete the process, go to your inbox, choose the desired folder, and click the Finish button.

Outlook’s keeps creating duplicate contacts problem has been solved. You should now have sufficient tools to eliminate unnecessary duplicates of contacts. As you can see, though, this method is challenging for users. Therefore, we propose a more sophisticated approach to eliminating duplicate contacts.

An Automated Method to Resolve Outlook Keeps Creating Duplicate Contacts Problem

Apart from the method mentioned above, you can use the Regain Outlook duplicate remover tool. It is an automated solution that removes duplicate emails, calendars, contacts, and other data from PST files in a single click.

Free Download100% Secure Buy NowPrice: $29

Using Regain Outlook duplicate remover tool, you can add multiple PST files to process and remove duplicate items simultaneously. The tool is very straightforward; even a newbie can remove duplicate items from PST files. Some of this tool’s glimpses are as follows:

  • The software allows to remove duplicate items in just a few clicks.
  • You can add multiple PST files to remove duplicates and process them concurrently.
  • Once you deduplicate the Outlook PST file, you can create the resultant PST file of the desired size.
  • The software doesn’t alter the PST file attribution and keeps folder hierarchy intact.
  • The software support PST files of all Outlook versions, including Outlook 2019, and also you can use the software with any Windows Operating system.

These are only a few features Regain Outlook duplicate remover tool provides. You can have a free version of the software and check its skills and compatibility before investing in the tool, preventing Outlook keeps creating duplicate contacts problem.


Having duplicate contacts in your Outlook program can put you in different types of trouble, so it is recommended to timely check for your data and use the necessary settings to prevent duplicity. However, I suggest using Regain Outlook duplicate remover tool as it is the most cost-effective and convenient solution. This write-up discusses the solution to prevent Outlook keeps creating duplicate contacts issue.

Author: Henry Bray

Henry Bray is a young technologist and content a Content Writer at Regain Software, loves to write about MS Outlook, MS Exchange Server, Office 365, Mozilla Thunderbird and many more email applications.

One thought on “Fix Outlook Keeps Creating Duplicate Contacts”

  1. Avatar Rishi says:

    Your information was quite useful in resolving the problem of Outlook producing duplicate contacts. I appreciate the clear explanation and the straightforward measures to take to resolve the problem. Thank you for the helpful advice!

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