How to Remove Duplicate Emails from Thunderbird Mailbox?

Mozilla Thunderbird is a desktop-based email client that allows users to send and receive messages from other users. Due to the fact that it is a mail-based program, it is likely that it contains duplicate emails. Thunderbird duplicate messages result in file size increases and take up a lot of storage space. In order to fix this problem, you have to remove all these duplicate messages from Thunderbird. But manually deleting messages is a very difficult and lengthy process. Here in this blog post, we’ll show you the best method to delete duplicate emails from Thunderbird in easy steps.

Due to several duplicate messages in Thunderbird mailboxes, the file size grows, taking up a lot of storage space. Various other problems users may also face while using Thunderbird. It is recommended to move from Thunderbird to Outlook in order to fix the Mozilla Thunderbird-related problems. Users can download a free Demo of this eSoftTools Thunderbird to Outlook Converter from here.


Reasons for Email Duplication

  • Users’ Accidental Activities:- If Thunderbird has more than one subfolder and you are copying mail to various directories, this can trigger an issue.
  • Server-Related Issues: Servers are essential for sending and receiving emails from email clients. But sometimes, issues arise in the server, resulting in the server’s poor behavior. As a result, it frequently downloads the same file, resulting in duplicate emails for users.
  • Sender Side Mistake:- Thunderbird saves repeat mail after receiving the first mail if the sender sent the same message over and over again for some of reasons.

How to Remove Duplicate Emails from Thunderbird?

  • Open Mozilla Thunderbird on your computer and select Tools >> Add-ons from the menu.
  • Add-ons Manager will now appear as a new tab. Type Remove Duplicates in the search box, then press the Enter button.
  • Look for the Remove Duplicate Messages add-on in the Available Add-ons list. To download this add-on into your Thunderbird program, click the Install button.
  • After completing the download process press the Restart now option, to activate the installed add-on.
  • Launch the Thunderbird application, then go to the My add-ons section.
  • Now you will see an installed remove duplicates add-on that will allow you for erasing duplicate emails.
  • Return to your account and right-click the mail folder (Inbox, Draft, or Sent) where you want to remove duplicate emails. Choose Remove Duplicate Messages from the menu that appears in front of you.
  • If the selected folder does not contain any duplicate messages, you will receive a message and must click OK to complete the procedure; otherwise, proceed to the next stage.
  • The folder containing duplicate messages will open in a new window called Duplicate Messages. This window will display the total number of emails in the selected folder, as well as the number of emails that will be deleted.
  • To delete all duplicate messages from your Thunderbird mail account, press the Delete Selected button.
  • Now delete duplicate messages by clicking on OK button.

A message will now appear at the bottom of the screen showing that unwanted messages are being moved to the trash folder. You can also delete all the emails from the trash folder by selecting them by pressing the with (Ctrl+A) and delete key on your keyboard.


As a result, we’ve outlined the most effective method for users to remove multiple duplicate emails from their Thunderbird mailboxes. To delete/remove redundant Thunderbird posts, simply follow the easy and reliable solution. If the issue continues, you can also try the method to import Thunderbird emails to Outlook.

Post a comment