How to Remove Duplicate Emails in Outlook? Step-by-Step Guide

Daily, the number of emails is increasing in our mailboxes. It becomes necessary to remove duplicate emails in Outlook mailbox, which can enhance performance and manage the data file size. Be careful while removing duplicate emails, as it might lead to storage space issues, slowing down Outlook performance, etc. So, to prevent these issues, this article will discuss the effective methods to delete duplicate emails in Outlook.

All such reasons make users think twice about how to deal with these duplicate emails in Outlook. Thus, to make this task easier, multiple ways to remove duplicate emails in Outlook.

Let’s learn and understand them one by one:

Important: Make sure to take backup of your Outlook mailbox before performing any of these methods. This way if something goes wrong, you will have the original mailbox file.

#Method 1: Import/Export Option to Delete Duplicate Emails

With the help of the Import/Export feature, you can also remove duplicate email messages in Outlook. This method allows you to remove duplicate items in Outlook by exporting your mailbox without duplicates and then re-importing it. Follow the steps mentioned below in two stages:

Stage 1: Export without duplicates

1. Open Outlook.
2. Now, go to File, then Open & Export, then Import/Export.
3. Here, select “Export to a File” and then choose Outlook data file (PST).
4. Select all the folders that you want to deduplicate.
5. Finally, choose “Do not export duplicate items” and finish the procedure.

Stage 2: Import without duplicates

1. Open Microsoft Outlook and navigate to File → Open & Export → Import/Export option

2. In Import and Export Wizard window, choose Import from another program or file option and click on the Next button

3. Now, choose Outlook Data File (.pst) on Import a file window and click on the Next button

4. On the Import Outlook Data File window, simply Browse the .pst file and check Do not import duplicates option → Next button

5. Now, choose Outlook Data File and select “Import to the same folder in:”. At last, select the mailbox from which the emails were exported in Stage 1 and click Done.

#Method 2: Use Clean Up Tool to Remove Duplicate Emails from Outlook

Microsoft Outlook has a Clean Up Tool that lets you delete duplicate items from Outlook. This built-in tool can serve as a basic duplicate email removal for Outlook by cleaning up conversations, folders, or subfolders. To use it properly, follow the steps mentioned below:

1. First of all, open the MS Outlook application
2. Then, click on the Clean Up tool from the ribbon bar and expand all the options.
3. As you expand it, three options will be displayed, i.e., Clean Up Conversation, Clean Up Folders, and Clean Up Folders & Subfolders.
   
4. Here, you have to choose Clean Up Folders & Subfolders option
5. Now, a Clean Up Folder dialog box will pop up, asking you whether to proceed with clean up or cancel. Simply, click on the Clean Up Folder option
6. After that, click on the Settings option to enter Deleted Items folder location manually
7. As you click on the Settings, an Outlook Options window will open. Click on the Browse button to add the PST file
8. Now, the Select Folder pop-up will appear in front of you. Choose Deleted Items → OK button
9. Finally, click on the Clean Up Folder option to remove duplicate emails in Outlook mailbox.

#Method 3: Deduplicate Outlook Emails in Preview Mode

This method relies on visually checking and comparing emails and then deciding on deletions. It works most efficiently when there are only a few duplicates in a known folder.

Steps to Use the Preview Method for Removing Duplicates in Outlook:

1. Switch to Preview Mode
   • Change the view of the PST folder containing duplicate emails to “Preview” mode in Outlook.
     
2. Differentiate Columns for a More Favourable Comparison
   • Access the View Settings menu.
   • Click on the Columns… button.
   • Select from the available columns for display by clicking Add (e.g. Size, Subject, Date, Sender).
3. Sort Emails to Easily Identify Duplicates
   • Click on a column header (for example, “Size”) to group emails according to shared characteristics.
   • Alternatively, use the Sort… button in View Settings and sort emails by Subject, Received Date, Sender, etc.
     • Go to View > View Settings > Sort…
       
     • In the Sort window, from the drop-down lists, select your sorting criterion and click OK.
     • Click OK again in the Advanced View Settings dialog box to save changes.
4. Manually Find Out and Delete Duplicate Emails
   • Once all emails are organised, you can start a visual comparison to determine which ones would be counted as duplicates.
   • Now, remove duplicate messages manually.

This method takes considerable labour, especially when there are a lot of emails organised into several folders. It would also require much effort to review the messages to make sure one does not delete that all-important email erroneously.

However, if it is only a few duplicates and they are all at one particular known location, this should work quite well for you. But perhaps for larger-scale removal of duplicate files, you might consider automated applications or other filtering methods as being more efficient.

Remove Duplicate Emails from Outlook Professionally

If a user is looking for a simple solution or wants to avoid the manual solution, go for a professional alternative automated solution that is SysTools Outlook Emails Duplicates Removing Tool which can help you to remove duplicate emails in Outlook effectively.

The software is designed to keep all the requirements of users in mind. One can find and remove duplicate emails in Outlook by matching particular attributes. For example, subject, to, cc, from, etc. In addition, a user can also delete duplicates from multiple PST files in bulk via Add Folder option. It can be treated as a one-stop solution to fulfil all the basic requirements of users. Along with this, the tool also offers the facility to remove duplicate attachments from Outlook.

Working of This Tool

1. Download and install the duplicate email removing utility.
   
2. Click Add File or Folder button to upload supported files.
   
3. You can choose between the two options to delete duplicates: Within or Across Folders.
   
4. Choose location to save the resultant PST file.
   
5. Choose data items, i.e., Emails, Contacts, Calendars, Journals, Tasks, and Notes, to remove duplicates.
   
6. Now, choose Specify Duplicate Criteria option to specify to remove duplicate emails in Outlook.
   
7. Click Next as you are done with the process of removing duplicate emails from Outlook.
   

Also Read: How to Combine PST Files Without Duplicates Emails?

Comparison of Outlook Email Duplicate Removal Options

Since the Preview method is all about finding and deduplicating emails by the user, we are not going to include it in the comparison table.

Features	Method 1: Import/Export Option	Method 2: Clean Up Tool	Method 3: SysTools Remove Duplicate Emails
Processing Speed	Moderate (depends on folder size)	Fast for small folders	Very Fast (batch processing)
Ease of Use	Moderate (multiple steps required)	Easy (built-in tool)	Very Easy (automated process)
Duplicate Detection Accuracy	Basic (matches exact duplicates only)	Moderate (considers message headers)	High (multiple matching criteria)
Batch Processing	✕ No	✕ No	✓ Yes
Custom Filters	✕ Limited	✕ Limited	✓ Advanced filtering options
Multiple Folder Support	✕ Single folder only	✓ Yes	✓ Yes (with subfolder support)
Cost	Free (built-in)	Free (built-in)	Paid (professional tool)
Data Safety	Moderate risk	Low risk	Very low risk (creates new pst)
Special Features	• Basic duplicate detection • Works with PST files	• Built-in Outlook integration • Simple interface	• Advanced matching algorithms • Multiple PST support • Selective deletion based on properties • Progress tracking
Best Suited For	Small mailboxes with exact duplicates	Regular maintenance of moderate-sized folders	Large mailboxes, multiple PSTs, and professional use
Pros	• No additional cost • Simple process • No installation required	• Built-in tool • User-friendly • Preview feature	• Comprehensive solution • High accuracy • Remove by Properties • Time-saving
Cons	• Limited functionality • Time-consuming • No preview option	• Limited filtering options • Single folder processing • Basic duplicate criteria	• Paid solution • Requires installation

Concluding Words

Handling duplicates is one of the difficult tasks faced by users. Thus, to make this task easier for the users, multiple ways to remove duplicate emails in Outlook. This blog has covered all possible manual and professional ways for the user. A user can pick between the discussed solutions to delete duplicate emails in Outlook as per his or her requirements.

FAQs on How to Remove Duplicate Emails in Outlook?