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Outlook Sending Multiple Emails with Attachments – Reasons & Solutions

Ugra Narayan Pandey | Modified: November 18th, 2022 | 6 Minutes Reading

“Last Week my Microsoft Outlook 2007 sends multiple copies of the same email. However, it is not happening with each and every email. But, sometimes it sends one email along with attachments around 20 or 30 time. Thus, it creating trouble for me as well as receiver to manage mailbox in a proper manner. Therefore, looking for a solution of how can I fix Microsoft Outlook Sending Multiple Emails with Attachments issue in an easy and simple way.”

Multiple copies of the same email become very irritating for both sender and receiver who send and receive that particular email. Managing the mailbox of Outlook in a systematic way becomes really difficult because the receiver will have that same email many times in the inbox and sender will have that same email many times in the sent items folder. Having duplicate emails in the mailbox is one of the most annoying things that irritate users the most.

This improper functioning of Outlook has now become the common problem of the email application users. Thus, this blog discusses the several causes and solution to resolve the Microsoft Outlook 2010 sending duplicate emails issue that a user can use without any hassle.

Author’s Advice: Improper functioning of Microsoft Outlook can damage the data file either a PST or OST file. Always take a backup of your current and healthy data file and keep safe from virus attacks. PST file is a default data file of Outlook 2019, 2016, 2013, 2010 and below versions. PST file stores all your Outlook mail profile emails, contacts, calendars, tasks, etc. As per suggestion always take a backup of Outlook data files and keep Outlook PST file error-free. There are many Outlook errors which occur PST file corruption, Use Outlook Recovery Software to keep Outlook data files healthy.

Outlook Sending Multiple Emails with Attachments

Why is Outlook Sending Multiple Emails with Attachments?

There can be several reasons due to which users face this repeated emails in Outlook problem and most common ones are discussed below:

Anti-Virus Integrated with MS Outlook

One of the major factors that Outlook sends multiple copies of an email is anti-virus software is integrated with MS Outlook application. The reason behind this is that anti-virus scans each and every outgoing email also due to which this duplicate emails issue occur more frequently.

Short Interval Between Send/Receive Connection

Another major cause of MS Outlook 2010 sending duplicate emails issue in the short time interval, for example, less than 6 minutes is set up between send/receive connection. It is because when the email is uploaded to the server, it can also be possible that next send/receive connection is build up before the first one completes. In this, sometimes message is still present in the Outbox and submitted again to send before it is received by the receiver. This is the most common reason due to which repeated emails are sent and receive again and again.

Due to Server Timeout

The IMAP and POP accounts are responsible for the slow connection to the mail host. It tells the Outlook when to consider that connection is lost i.e. when no response is generated from the server in the default time i.e. 1 minute. It is the time when the connection is really weak and reaches to timeout. Due to this, it resends the message when the Send/Receive connection is rebuilt. This will generate the multiple copies of the message when submitted to the server and there is no acknowledgment message received before timeout.

These are all the major factors that send multiple copies of the same email. As know it is pretty much clear why this issue arises in MS Outlook. Therefore, now it is easy for a user to tackle the problem and fix Outlook 2007 sending duplicate emails issue.

Approaches to Fix the Outlook Sending Multiple Emails Error

There are different approaches available that a user can use to solve this Outlook is sending multiple copies of the same email problem. However, solution to fix the Outlook varies from cause of the occurrence. Thus, here in all possible solutions depending upon the cause are covered.

Approach 1: Turn off Integrated Anti-Virus

If Outlook sending multiple copies of email with attachments, it is always suggested to turn off the anti-virus if it is integrated with MS Outlook. Because it does not create any problem but increase the performance of Outlook. After that, a user can try to send the message, it does not generate duplicates then, the problem is due to anti-virus only.

Approach 2: Increase Time Between Send & Receive Connection

A user can increase the time interval between send & receive connection to check if Outlook 2007 is sending duplicate emails or not. Now, to do the same, follow the steps below:

In Outlook 2007 & below versions

  • First, click on Tools and choose Send/Receive option
  • After that, click on Send/Receive Settings and then on Show Progress

In Outlook 2010 & all above versions

  • To begin, click on the Send/Receive tab
  • Then, click on Show Progress option

If there are more than two tasks present in the dialog box, means send/receive time interval is set to very small.

Increase the time interval by the following the steps given below:

  • First of all, besides the Send/Receive Groups, choose the downward arrow
  • After that, choose the Send/Receive Groups option
  • Now, change the time interval from Schedule an automatic send/receive every option

Outlook 2007 is Sending Duplicate Emails

Note: It is always advisable that do not set the time short than 5 minutes. However in the case of multiple accounts, set it more than 10 minutes.

Approach 3: Increase the Server Timeout

By default, the mail host timeout is set to 1 minute for POP and IMAP accounts. Therefore, it is always suggested to increase it to 2 to 3 minutes. However, not exceed it to more than 3 minutes. Now, to do the same follow the steps given below:

  • First of all, click on File >> Account Settings option
  • After that, double-click on IMAP/POP3 account
  • Now, from the dialog box, click on More Settings option
  • Next, click on the Advanced tab in the Change Account box
  • Then, go to the Server Timeout section and increase the time

Outlook Sending Multiple Emails

  • After changing time interval, Click on OK button


To maintain the continuity of work, emails always play a vital role. However, there are some situations in which Microsoft Outlook sending multiple emails with attachments, which creates trouble for a user. Therefore, in this blog, all causes that raise this issue with their respective solutions are discussed. One can easily refer them and resolve duplicate emails issue from MS Outlook.