Microsoft Outlook Sending Multiple Emails – Approaches to Troubleshoot

admin | October 31st, 2017 | Windows Outlook

Effective Ways to Fix Microsoft Outlook Sending Multiple Emails Issue

There is a very common problem discussed repeatedly in many forums and blogs nowadays. Many users are worried that why is Microsoft Outlook sending multiple emails? It is a peculiar situation where a recipient receives multiple copies of a certain email. This post sheds some light on this issue and discusses it a bit further. Manual solutions have been discussed here that might be used by anyone easily. Read this article to find out how.

Reasons that Lead to Multiple Emails Sent From Outlook

Following are some of the various reasons that cause multiple emails being sent from Outlook application:

File Scanners: Any antivirus installed may detect a corruption in a PST file and quarantine it. This may lead to errors and bugs in Outlook application. It is the leading cause for multiple email copies received Outlook.

Slow Internet Connection: An acknowledgement message is sent by IMAP and POP protocols when an email is delivered. This notifies Outlook on the successful delivery of the message and it is deleted from the Outbox. If the internet connection is slow, the acknowledgment message is never received and the email stays in the Outbox. So, in the next Send/Receive cycle, the email is sent again causing multiple email copies received in Outlook.

Short Send/Receive Timing: It may happen that the application starts to send and receive again, very soon after its first cycle. This can lead to multiple copies of the same message being sent again and again.

Methods to Fix Microsoft Outlook Sending Multiple Emails Issue

Here are some of the manual ways to recover Outlook from a situation where it is sending multiple copies of the same email:

Solution 1: Disable Antivirus Scanner

To disable the anitivirus scanner, follow the steps:

  1. First, try to disable any file scanner installed on the Windows PC.
  2. Then, send the message again and ask the receiver if the issue persists.
  3. If it does not, uninstall the antivirus scanner to fix Outlook 2016 sending multiple copies of email issue.
  4. Or visit the software website to learn steps how to configure the scanner with Outlook.

Solution 2: Increase Send/Received Cycle Timing

Follow the steps given below:

  1. First, go to Outlook 2010, 2013, 2016 and select the Send/Receive tab.
  2. From there, click on Show Progress button.
  3. From Send/Receive Groups dialogue box, check if there are more than one tasks.
  4. If they are, it means that the Send/Receive interval is set to very short time causing multiple emails sent from Outlook.
  5. Then, click on the downward arrow key in the Send/Receive Groups dialogue box.
  6. From the Send/Receive Groups drop-down box, select Define option.
  7. Check the Schedule an automatic send/receive every box and set a time for than 5 minutes.
  8. Click OK button to confirm changes.

Solution 3: Increase Server Time-out to Fix Outlook Outbox Error

To increase the sever time-out follow the given steps:

  1. First, go to Outlook >> File >> Account Settings.
  2. Next, choose the account having trouble and select More Settings from the mini toolbar.
  3. From the Chang Account dialogue box, select the Advanced tab.
  4. From the Server Timeout header, move the slider to increase the time between 2 to 3 minutes.
  5. Then, click OK button.

In most of the cases, the above solutions fix the issue of Microsoft Outlook Sending Multiple Emails the above solutions

Solution 4:Clear Outbox Folder to Remove Outlook Sending Multiple Email Copies

To clear the Outbox folder:

  1. First, open Outlook 2003, 2007, 2013 or 2016 application.
  2. Then, go to Outbox folder by clicking on small + symbol next to Personal Folders on the left pane.
  3. On the centre pane, a list of all emails stuck in Outbox can be seen.
  4. Delete the messages one by one by right-clicking on them and selecting Delete option.

Solution 5: Check Outgoing Mail Server to Repair Outlook Outbox Error

Check the Mail server:

  1. Go to MS Outlook >> File >> Account Settings.
  2. From the Account Settings dialogue box, select the ID having issues from the E-mail tab.
  3. Now, click on Change button from the mini navigation bar.
  4. From the Change Email Account screen, go to More Settings >> Outgoing Mail Server.
  5. Check the port number and SMTP settings.
  6. Then, click OK to save the changes made. Restart Outlook and try sending the message again to verify whether the issue persists.


It can be very unprofessional if a client or customer receiving too many copies of same message over and over again. This may result in some users spamming the ID through which the mail is sent. There can be lots of reasons why Microsoft Outlook sending multiple emails. Some of the solutions to fix this issue are discussed in this post. These manual solutions have also been described to stop the MS Outlook messages being sent again and again.