Quickly delete, move, or categorize duplicate emails in Outlook
Kutools for 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.
- To delete specific duplicates, simply check them in the Duplicate Email List box and then click the delete button.
- Emails are considered duplicates if the subject, body and attachment names are the same. All three criteria must be met for an email to be classified as a duplicate.
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.

- 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.
- 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.
- Right-clicking the duplicates list will open the right-click menu where you can easily expand and collapse the list by clicking the appropriate option.
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.
- To delete specific duplicates, simply check them in the Duplicate Email List box and then click the delete button.
- Emails are considered duplicates if the subject, body and attachment names are the same. All three criteria must be met for an email to be classified as a duplicate.
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.

- 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.
- The Body, Attachment and Subject fields are checked by default. Emails will be considered duplicates only if these three conditions are all matched. You can specify your own fields if you need.
- If you want to find duplicate emails across selected folders, check the Search duplicate messages across folders box. Otherwise, the search for duplicate emails will be limited to individual folders.
4. In the Duplicate Emails – Step 3 wizard, choose one results display mode and click the Start filtering button.
- The Default option is selected by default, which means that the file path, subject and body fields will be listed in the filter result.
- You can specify the fields you need to display in the filter result. Just select the Custom option and then check the fields you need in the Duplicate Mails -Setting dialog box and save the settings
- If you choose the Selected duplicate criteria option, the filter results will list the condition fields you specified in step 3.
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.
- 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.
- 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.
- 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:
- 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.
- 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.
- 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.
- Click the Done button to close the wizard.
Categorize all duplicate emails
To categories all duplicate emails, you need to do as follows:
- 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.
- 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.
- 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.
- Click the Done button to close the wizard.

Except for deleting, moving, or categorizing all duplicate emails listed in the wizard, you can also use the right-click menu to manage specific items of your choice.
Delete, move, or categorize all duplicates in a duplicate group
If you want to handle all duplicates in a certain duplicate group, right click on the group name and then choose the option you need.
- Selecting any option in the right-click menu will bring up a prompt box to confirm the action, click the Continue button if you want to continue, or click Cancel.
- Next you need to take note of the following
- If you choose to categorize all checked items in the current group, after confirming the action, a Color Categories dialog box then pops up for you to assign color categories.
- If you choose to move all checked items in the current group, after confirming the action, a Please select folders dialog box then pops up for you to choose a destination folder.
- If you choose to delete all checked items in the current group, after confirming the action, all duplicates except the reserved email will be removed immediately.
Delete, move, or categorize a certain duplicate in a duplicate group
If you only want to handle a certain duplicate email in a duplicate group, right click on that duplicate and then choose the option you need. See screenshot:
- Selecting any option (except the Set as reserved email option) in the right-click menu will bring up a prompt box to confirm the action, click the Continue button if you want to continue, or click Cancel.
- Next you need to take note of the following
- If you choose to move this item, after confirming the action, a Please select folders dialog box then pops up for you to choose a destination folder.
- If you choose to categorize this item, after confirming the action, a Color Categories dialog box then pops up for you to assign color categories.
- If you choose to delete this item, after confirming the action, all duplicates except the reserved email will be removed immediately.
Change the reserved email
If you need to change the reserved email, right click on the duplicate email you want to set as the new reserved email, and select the Set as reserved email option from the context menu.
Easily use the same settings the next time you search for duplicate emails
Once you have applied the advanced Duplicate feature, it will retain the last configurations, allowing you to easily use the same settings the next time you search for duplicate emails. To do this, simply select Kutools > Duplicate > Advanced Duplicate and, in the Duplicate Emails – Step 1 wizard, click the Start Filtering button.
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