How to delete all duplicate emails from a mail folder in Outlook?

Author: Kelly Last Modified: 2024-12-30

Sometimes, duplicate emails occur in Outlook because of downloading emails repeatedly, copying, importing from PST/CSV files, or other reasons. And this article is going to introduce two solutions to delete all duplicate emails from a mail folder in Outlook.

Delete all duplicate emails from a mail folder by sorting
Delete all duplicate emails from one or multiple mail folders with Kutools for Outlook
Delete all duplicate emails from multiple selected ones with Kutools for Outlook

Delete all duplicate emails from a mail folder by sorting

This method will guide you to sort all emails in a mail folder by subject, received time, sender, and attachments successively firstly, next manually pick out duplicate emails, and finally delete them. Please follow below steps:

1. In the Mail view, click to open the mail folder that you need to remove duplicate emails from.

2. Click View > Reading Pane > Off to turn off the reading pane. See screenshot:
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3. Click View > View Settings to open the Advanced View Settings dialog box.
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4. Now in the Advanced View Settings dialog box, please click the Sort button.
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5. Then the Sort dialog box comes out. Please select Subject from the Sort items by drop down list, select Received, From, and Attachment from below Then by drop down lists successively, and click the OK button. See screenshot:
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6. Click the OK button in the Advanced View Settings dialog box to save the sort settings.
Now it returns to the opening mail folder, and all emails are sorted by subject, received time, sender, and attachments successively.

7. Go ahead to click the From column header to group all emails by senders. See screenshot:
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8. Holding the Ctrl key, select duplicate emails one by one manually; and then press the Delete key to remove them. See screenshot:
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So far it has removed all duplicate emails in the selected mail folder already.

Delete all duplicate emails from one or multiple mail folders with Kutools for Outlook

With Kutools for Outlook's Quick Scan and Remove Duplicate Emails feature, you can efficiently clean up duplicate emails in one or multiple folders at once. Here's a step-by-step guide to help you.

Step 1. After installing Kutools for Outlook, open Outlook and click on the Kutools Plus tab in the ribbon, then click Duplicate Emails > Quick Scan and Remove Duplicate Emails.

Step 2. In the Duplicate Emails dialog, tick the folders that you want to remove duplicate emails from. Click OK.

Note: By default, it will tick all inboxes across accounts in Outlook.

All duplicate emails with matching subjects, attachments, and bodies will be displayed in the dialog.

Step 3. Click the Delete button to remove all duplicate emails. A confirmation dialog will appear, showing the number of deleted items. Click OK to close the dialog.

Now the duplicate emails in the selected folder(s) are removed off.

Take Attention

This feature identifies duplicate emails based on matching subjects, attachments, and bodies. If you want to customize the criteria for identifying duplicates, you can use the Advanced Scan and Remove Duplicate Emails feature, which allows you to set your own criteria.

Delete all duplicate emails from multiple selected ones

In fact, even if you have sorted emails by subject, received time, sender, and attachments, it might be not easy to pick out all duplicate emails manually. This article will introduce Kutools for Outlook’s Duplicate Mails feature, which can quickly remove all duplicate emails with only several clicks.

1. Open the mail folder, holding Ctrl or Shift keys to select multiple emails, and click Kutools > Duplicate Emails > Remove Duplicate Emails from Selected

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2. Now all duplicates among the selected emails are listed and marked with strikethrough. Please click the Delete button.

3. Now a dialog comes out and tells you how many duplicated emails are removed. Please click the Yes button to close it. And then click Close button to close the Duplicate Emails dialog