Microsoft Outlook is frequently use in our life. But, have you ever noticed that there are duplicate emails in Outlook? Have you been confused about those duplicate emails? Today, let’s talk about Outlook remove duplicate emails!

Part 1: Why We Remove Duplicate Emails in Outlook?

Microsoft Outlook is a highly used software in our computer. However, too many duplicate emails will cause bad performance of Outlook, even our computer.

  • Duplicate emails will confuse you: whether I have replied this email
  • Duplicate emails will take you more time when you search for some email
  • Duplicate emails will increase the size of Outlook data files, which may cause corruption in Outlook data files or slowness of Outlook
  • Duplicate emails will occupy more space of the computer which may influence the performance of the system

To avoid these possible issues, we need to remove duplicate emails in Outlook.

Part 2: What Result in Duplicate Emails in Outlook?

1. Repeated Downloading

When your network is poor, to download email, you may repeat to click to download the email. And the same email will occur in your Outlook.

2. Incorrect Configuration Rules

The wrong configuration of rules may result duplicate emails when you received emails.

3. Low Frequency in Outlook

The short intervals in sending and receiving emails and the low frequency of Outlook may result repeated synchronization of emails.

4. Incorrect Settings in Mailbox

The incorrect settings in mailbox can also result duplicate emails in mailbox.

5. Multiple Outlook Data Files Imported

If you have multiple Outlook data files and import them into Outlook, this may cause duplicate emails as well.

Part 3: How to Remove Duplicate Emails in Outlook?

Then here comes the question, how to remove duplicate emails in Outlook 2007, 2010, 2013 and 2016? Here we offer 8 methods for you.

1. Use a Third Party Software

The easiest way to remove duplicate emails is to use a third party software. Here we take Stellar Duplicator for Outlook as an example.

1. Install and run Stellar Duplicator for Outlook.

2. Click the icon of Outlook on the interface, then the folder list will pop up. Select the file you want to scan and remove duplicate emails, and click “Next”.

select folder to remove duplicate emails

3. Choose options in “Select Time Span” “Select Comparison Criteria” and “Action” according to your requirement, and click “Run Process”.

select options and click run process to start scanning

4. As soon as the process completes, click “OK” to finish.

click ok to complete the process

2. Check Outlook Rules

Go to check rules of Outlook are configured correctly. The wrong configuration of Outlook rules will cause duplicate emails. So you should check it first.

3. Delete Duplicate Emails Manually

The most original way to remove duplicate emails in Outlook 2016, 2013, 2010 or 2007 is to sort emails and remove duplicate emails manually.

1. Open the folder you want to remove duplicate emails in Outlook.

2. Click “View” tab, turn off reading pane by selecting “Off” in “Reading Pane” options.

select off in reading pane to turn it off

3. Click “View Setting” to open it.

click view settings to open

4. Press “Sort” button in the dialogue.

click sort to remove duplicate emails

5. Choose options in the dialogue to set limitations and click “OK”.

choose options to set limitations to sort emails

6. Hold “Ctrl” key and select duplicate emails and press “Delete” key.

4. Set Update Frequency

Before remove duplicate emails in Outlook 2010, 2007, 2013 and 2016, you can first check update frequency.

1. Go to “Send and Receive” in Outlook, click “Define Send” or “Receive Groups”.

2. Manage “Schedule an automatic send/receive every”, set it to 15-30 minutes.

set schedule an automatic send or receive every to 15 to 30 minutes

5. Remove Duplicate Accounts

To remove duplicate emails in Outlook 2013, 2010, 2016 and 2007, you can remove duplicate accounts first.

1. Open Outlook and click “File”.

2. Choose “Info” in options, select “Account Settings’.

choose account settings in info options

3. Select “E-mail” tab, and remove duplicate accounts.

remove duplicate accounts in email tab

6. Import without Duplicates

1. Go to “File” options in Outlook, click “Open & Export” tab and choose “Import/Export”.

choose import or export in open and export

2. Select “Import from another program or file” and click “Next”.

select import from another program or file

3. Click “Outlook Data File (.pst)” and press “Next”.

select outlook data file and click next

4. Click “Browse” to select file and pick “Do not import duplicates”.

click browse to select file and select do not import duplicates

5. Import to selected file and click “Finish”.

7. Use Inbox Clean Up

1. Launch Outlook, in “Home” tab, click the arrow next to “Clean Up”.

2. Select one option to remove duplicate emails in Outlook.

choose one option in clean up to remove duplicate emails

Then follow the instructions to remove your duplicate emails.

8. Disable Email Protection

The settings in anti-virus application sometimes can result duplicate emails in your mailbox. Under this circumstance, you can got to anti-virus application to disable email protection. And then remove duplicate emails in Outlook.

Bonus Tip: How to Recover Outlook PST File

What to do when you deleted emails in Outlook accidentally or your PST file is corrupted. Try Stellar Repair for Outlook. With this powerful tool, you can easily recover your PST file in Outlook 2019, 2016, 2013, 2010, 2007, 2003, and earlier versions. Here are the detailed steps on how to recover Outlook PST files.

1. Launch Stellar Repair for Outlook.

2. Tap “Select Outlook PST”, choose “Browse” or “Find” to select PST file need to be recovered.

click browse or find to select PST file

3. Press “Repair” button to start the process.

4. After repairing you can choose the file in left pane to preview.

click the file to preview

5. Click “Save Repaired File” in the “Home” tab. Choose format of the file and click “Browse” to select destination to save the file.

select the format of the repaired file and click browse to select destination to save


We have introduced 8 ways to help you remove duplicate emails in Outlook in this article, and recommend an amazing tool - Stellar Repair for Outlook, to recover Outlook PST file. If you like this article, please share it with others. And if you meet problems on Office password, try PassFab for Office.