This section will walk you through configuring the Send/receive settings and prevent Microsoft Outlook from downloading duplicate emails from mail sever. Please do as follows:

1. Open the Send/Receive Groups dialog box:
A. In Outlook 2010 or later versions, click the Send/Receive Groups > Define Send/Receive Groups in the Send & Receive group under Send / Receive tab.
B. In Outlook 2007, click the Tools > Options, and then click the Send / Receive button under the Mail Setup tab.

2. In the Send & Receive Groups dialog box, click the Edit button.

3. In the new opening Send & Receive Setting – All Accounts dialog box, select the email count in the left bar, and then click the Account Properties button.

4. In the Internet E-mail Settings dialog box, go to the Delivery section under the Advanced tab, and disable the Leave a copy of messages on the server temporarily.

5. Click OK button to exit the dialog box. After you configuring the accounts’ setting, it will automatically avoid downloading duplicate emails that caused by multiple email accounts receiving same emails.

Note: The above method is valid for POP3 email account type. If your Email account type is SMTP, for example the Gmail, you are not able to find the Delivery section under Advanced tab in the above Step 4.

Quickly search and delete duplicate emails in Outlook

With Kutools for Outlook’s Duplicate Emails feature, you can quickly find and delete them from multiple mail folders, or find and delete all duplicates from the selected ones with two clicks in Outlook.