How to Remove Duplicate Emails From Thunderbird



Mozilla Thunderbird is a desktop-based email application that allow users to exchange information among different users. Since it is a mail based application, then it is also possible that it could contain some duplicate mails within it. Thunderbird duplicate messages lead to increase in file size and also occupies large amount of storage space. Therefore, in order to delete all duplicate messages from Thunderbird, there is a need for a solution by which one can erase these email copies without facing any trouble in case of MBOX migration to Outlook.

Causes of Such Email Duplication

There are many reasons due to which situation occurs and some of them are mentioned below:

1. Issues Related to Server: Sometimes there occurs a problem in the server, which leads to irrelevant behavior of the server. It repeatedly download one mail again and again causing a trouble for computer users.

2. Accidental User Activities: Without any intention, clients copy a mail to any other subfolder of their mail application which causes duplication in Thunderbird.

3. Issues From Sender’s Side: Sender may send one mail repeatedly to receive for any kind of purpose, which also leads to Thunderbird receiving duplicate emails on receiver’s end.

The newly generated archive folder can be located in the Thunderbird folders.

Thunderbird Remove Duplicate Messages With A Stepwise Procedure

1. Launch Mozilla Thunderbird application on your machine and then go to Tools >> Add-ons option.

2. A new tab named as Add-ons Manager will open. In search text box of the current tab, write Remove Duplicates and then press Enter

3. Under Available Add-ons section, you will find Remove Duplicate Messages add-on. Click on Install button of this add-on in order to download this add-on in your Thunderbird application.

4. After successful completion of downloading operation, click on Restart now option for activating the installed add-on.

NOTE: You can skip step 1 to 4 if your Thunderbird application is already having Remove Duplicates plug-in.

5. When Thunderbird application gets restarted, perform Step 2 (again) and then go to My add-ons section.

6. Here you will find installed remove duplicates add-on that will denote that your application is having a plugin for erasing duplicate emails.

7. Now go back to your account and right click on the mail folder (Inbox, Draft, and Sent) from which you want to delete duplicate emails. From the menu appearing in front of you, choose Remove Duplicate Messages option.

8. If the selected folder is not having any duplicate messages within it, then you will encounter a message & you will have to click on OK and end the procedure; else continue with next step.

9. The folder that is containing duplicate within it will open a new window i.e.,Duplicate Messages window. This window will describe the total number of emails present in the selected folder and number of emails to be deleted (since they are duplicate).

10. Now click on Delete Selected button in order to erase all the duplicate messages from Thunderbird mail account.

11. Click on OK button to erase duplicate messages from source folder.

12. On the bottom of screen you will find a message indicating that unwanted messages are moving to trash folder. Moreover, you can delete all the emails from trash by selecting them (Ctrl+A) and pressing delete button from keyboard.

Alternative Approach to Remove Duplicates

The approach involves following set of steps:

  • Select duplicate emails from each folder (one folder at a time).
  • Press Delete button in order to move them in trash folder.

This procedure is quite irrelevant when the duplicates are to be removed from numerous folders and also cause a lot of confusion while deletion procedure. It consumes a lot of time if there exits bulk amount of email copies.

Hope the above steps helps the users to remove duplicate emails and can perform Thunderbird data to Outlook conversion also.