Troubleshooting for Error message 0x80040109 in MS Outlook

Yesterday, when I was trying to send a mail from my Outlook account, all of sudden I received an error message says:
 “0x80040109 – The Operation cannot be performed because the message has been changed”.

I tried to find a solution to fix the problem, I Uninstalled my antivirus and then reinstalled it without e-mail scanning feature. And Yeah! It worked. After that everything was working fine.

If you are facing the same problem then reading this article may help you.

Let’s have a brief introduction with the error: 
Error Message - 
(0x80040109): 'The operation cannot be performed because the message has been changed.'

This error occurs when third party software (such as desktop search or backup software) tries to change the email message in between the sending process. The Antivirus software or firewall installed on your system can also lead this error.
This error may cause problem while sending Emails. It can also cause calendar or contacts duplicates because due to this error the MS outlook couldn’t save the record of previously migrated messages. When you re-start the migration process then 'Only New Data' is checked and the previously migrated messages will be migrated again.

Solution:
Before trying to resolve this problem you must know that which application is causing the problem.
To determine which add-in is causing this issue you need to Start Outlook in safe mode and verify the result:
Follow the below steps to Start Outlook in safe mode:

• Hold Windows key + R.
• Type the following command “Outlook  /safe” in the Open box
• Press Enter.

Now, disable each add-ins one by one to determine the problem causing add-in.

a) Click >File > Options >Add-ins >Go button besides Manage: Com-in Add.
b) Clear the checkbox if add-ins are listed there
c) Close the MS Outlook application and restart it.
d) Disable each add-in one at a time, restart the Outlook, and repeat the above procedure.
If the issue reappears again, it will help you to determine error causing add-in.

So, here is the solution

• If your antivirus or firewall is causing this error then, disable email scanning and then restart Outlook.
• If the issue is due to any other add-in, then uninstall and re-install the application. You can also rectify your problem by checking the program support to rectify the conflict.

 I hope this article is going to help you to fix outlook PST file. To get more updates keep reading my blog. Your valuable feedback & suggestions are welcome.