Removing duplicate emails in Thunderbird

Question

I need to stop the duplicate mail (which is already in my mail box) in Thunderbird or any mail box.

Are there any filters for this?

Answer 1

Try reading this

It has a couple of suggestions for extensions to delete duplicates and also has some tips on avoiding them in the first place.

Answer 2

The kind of de-duping that you're asking for is usually configured on the server. For example, one can configure Microsoft Exchange to recognize that a particular user is also on a distribution list, and only send one copy:

http://technet.microsoft.com/en-us/library/dd577073%28EXCHG.80%29.aspx

On the client side, your only real option is to create a filter. Differentiating the two emails is not immediately obvious to me. Here's what I would do:

1. In firefox, double click both emails to open them in separate tabs
2. For each email, choose View->Headers->All
3. Compare the headers in both and see if you can determine a differentiating factor
4. If you succeed in (3), then create a custom filter and delete the message based upon the header.

Answer 3

Or try some add-Ons:

Like this, https://addons.mozilla.org/en-US/thunderbird/addon/remove-duplicate-messages/

or read this: http://email.about.com/od/mozillathunderbird/gr/remove_duplicat.htm

Answer 4

I believe there's more development effort behind the "Alternate" version of the "Remove Duplicate Messages" add-on. (Last update March 11, 2011 as of this writing). This is the one I use.

https://addons.mozilla.org/en-US/thunderbird/addon/remove-duplicate-messages-alte/

Note that it refuses to work on "special" folders by default, and you have to enable this option in the settings: → "Message Comparison" tab → UNcheck "Skip Special Folders (Sent, Drafts etc.)."

I've used this extension on several thousand messages at once (merging mail archives from different mail clients that had used POP to fetch mail) and it hasn't burned me yet. You probably won't want to try it on one of Thunderbird 3's new "unified" folders, as I'm not sure that will turn out too well. Rather, switch to the "All Folders" view and select two individual folders using the context menu option Set original message folder(s) for next duplicate search.

And make backups.