Quickly delete, move, or categorize duplicate emails in Outlook

When you want to delete all your duplicate emails at once, unfortunately, Outlook doesn't offer a built-in solution. Usually, you have to manually delete them one by one or look for a useful add-in to assist in this task. Kutools for Outlook is a valuable add-in designed to increase your productivity in Outlook. With Kutools for Outlook's Duplicate utilities, managing duplicate emails is a snap, allowing you to quickly batch delete, move or categorize them.

• Delete duplicate emails within selected emails
• Delete duplicate emails from specified folders
• Delete, move, or categorize duplicate emails from specified folders

Delete duplicate emails within selected emails

To delete duplicate emails within selected emails, the Selected Emails feature of Kutools for Outlook can help you easily get it done. Please do as follows.

1. Open an email folder and select the emails that you want to remove duplicates within them.

• Holding the Ctrl key, you can select multiple nonadjacent emails by clicking them one by one in the message list.
• Holding the Shift key, you can select multiple adjacent emails by clicking the first email and the last one in the message list.

2. Select Kutools > Duplicate > Selected Emails.

3. Then a Duplicate dialog box will pop up, listing all duplicates within the selected emails. Then you can click the Delete button to start all deleting duplicate emails.

Tip: All duplicate emails are checked by default. If you don't want to delete all duplicates, you can expand the duplicate group and check only the duplicates that need to be deleted.

4. A Duplicates Mails – Kutools dialog box will then pop up to remind you how many duplicate emails you have deleted. Click OK to close this dialog box.

5. Now, all duplicate emails have been deleted, leaving only one copy (the email showing the red dot in the lower right corner of the email icon). You can click the Finish button to close the dialog box.

Delete duplicate emails from specified folders

In the above section, I described how to delete duplicate emails from selected emails, here, I will describe how to delete duplicate emails from specified folders using the Delete Duplicate Emails in Folders feature of Kutools for Outlook.

1. After installing Kutools for Outlook, select Kutools > Duplicate > Folder Emails.

2. In the Duplicate Emails – Select Folder dialog box, you need to configure as follows.

2.1) Select the email folders from which you want to delete duplicates.

2.2) Click OK to continue.

Tips:

• If you want to find duplicate emails across selected folders, check the Cross-file Filtering box. Otherwise, the search for duplicate emails will be limited to individual folders.
• There are more operations in the right-click menu to help you quickly select folders. See screenshot:
  

3. Then a Duplicate Emails dialog box will pop up, listing all duplicates within the selected emails. Then you can click the Delete button to start all deleting duplicate emails.

4. Then a Duplicates Mails – Kutools dialog box will pop up to remind you how many duplicate emails you have deleted. Click OK to close this dialog box.

5. Now, all duplicate emails have been deleted, leaving only one copy (the email showing the red dot in the lower right corner of the email icon). After finishing the deletion, close the dialog box.

Delete, move, or categorize duplicate emails in specified folders

Besides the above two features, Kutools for Outlook also offers a feature called Advanced Duplicates. This feature does more than just delete duplicate emails in specified folders based on your set filters; it also enables moving and categorizing of those duplicates.

1. After installing Kutools for Outlook, select Kutools > Duplicate > Advanced Duplicate.

2. In the Duplicate Emails – Step 1 wizard, you need to configure as follows.

2.1) Select the email folders from which you want to delete duplicates.

2.2) Click the Next: Select fields to filter duplicate emails button to continue.

Tips:

• Right click the Folder name list, you can easily check, uncheck, select, unselect, expand, or collapse all folders as you need with the right-click options.

• The selected folders are listed on the right side of the wizard, and messages within the upper folder will be prioritized to be retained.
• You can select one of the folders and then click any of the move icons to rearrange the selected folder as needed.
• You can delete a folder by selecting it and click the Delete button.
  

3. Now you get into the Duplicate Emails – Step 2 wizard. In this wizard, you need to specify the conditions to determine duplicate emails and click the Next: Select the fields to be listed in the results button.

4. In the Duplicate Emails – Step 3 wizard, choose one results display mode and click the Start filtering button.

5. In the Duplicate Emails – Step 4 wizard, a Kutools for Outlook dialog box will firstly pop up to remind you about the filter completion, click the OK button. Then all duplicate emails in selected folders are listed in the wizard. Then you can delete, move, or categorize the duplicate emails as follows.

Delete all duplicate emails

To delete all duplicate emails, please configure as follows in the Duplicate Emails - Step 4 wizard.

1. Click the Ways to handle duplicate Email drop-down list, choose the Delete (move to the Deleted Items folder) option, and then click the Apply now button.
   
2. This will bring up a Kutools for Outlook dialog box telling you how many duplicate emails have been deleted, click OK to close the dialog box. You will see the duplicate emails except for the reserved email (one with a red dot displaying in the lower right corner of the email icon) listed in the wizard with a strikethrough added.
   Tip: These emails with a strikethrough added have been deleted from the specified folders.
   
3. Click the Done button to close the wizard.

Move all duplicate emails

If you need to move all duplicate emails to a specified folder rather than remove them, you can do as follows:

1. Click the Ways to handle duplicate Email drop-down list, choose the Move duplicates (except reserved) or Move all duplicates (including reserved) option, and then click the Apply now button.
   Tip: The reserved email is the one with a red dot displaying in the lower right corner of the email icon.
   
2. A Please select folders dialog box pops up, you need to select or create a folder to save the duplicates and then click the OK button.
   
3. Then a Kutools for Outlook dialog box pops up telling you how many duplicate emails have been moved, click OK to close the dialog box. You will see the duplicate emails listed in the wizard with a strikethrough added.
   Tip: These emails with a strikethrough added have been moved to the specified folder.
   
4. Click the Done button to close the wizard.

Categorize all duplicate emails

To categories all duplicate emails, you need to do as follows:

1. Click the Ways to handle duplicate Email drop-down list, choose the Add categories (including reserved) option, and then click the Apply now button.
   Tip: The reserved email is the one with a red dot displaying in the lower right corner of the email icon.

2. In the opening Color Categories dialog box, check one or more categories as you need and then click OK.
   
   Note: If this is the first time you have used the categories, a Rename Category dialog box will open, you can choose whether to rename the selected category or not based on your needs.
3. Then a Kutools for Outlook dialog box pops up telling you how many duplicate emails have been categorized, click OK to close the dialog box. You will see the duplicate emails listed in the wizard with a strikethrough added.
   Tip: All listed duplicates, including the reserved ones, have had the specified category added.
   
4. Click the Done button to close the wizard.