Rated 5 out of 5 stars

Great tool, perhaps to help others migrating a large mail account to Thunderbird I came across a hidden limit of 10000 mail items in the defaults/preferences/removedupes.js file, that seemed to be stopping the search process and isn't visible as an adjustable parameter in the settings available from the add ons section of the Thunderbird menu.
Method I used was to save the xpi file to a drive location, change the extention to .zip, open the removedupes.js with Notepad++ and change the default value of the line:
pref("extensions.removedupes.processed_messages_limit", 10000);.I also changed the line pref('extensions.removedupes.yield_quantum',20000); (from 2500 to 20000).
Simply save the file once edits have been made and then send all the files to a .zip and then rename the extension back to .xpi. Use the "install add on from file" in the Add ons Manager (settings icon near top centre - looks like a gear/cog) and job done.

Rated 5 out of 5 stars

Very useful Tool.

Currently I am transfering from Windows 7 to Linux Mint and in the meantime I use Thunderbird with both OS, hence I have many mail duplicates.

Had also the Problem that no duplicates were found. After I cleared the "SIze"-Check it worked well.

I also appreciate these many settings for the tool , e.g. that you can search all subfolders, which is a default setting.

Rated 5 out of 5 stars

Works well for me.

@Konrad65 @ChrisInVT I needed to open the preferences for the add-on via the menus:

Tools > Add-on Preferences > Remove Duplicate Messages

I then unticked "Size", and then it found duplicate messages.

I believe this is because the size of the duplicates is different to the originals because new headers were inserted into them.

Rated 1 out of 5 stars

Doesn't actually do anything. My Gmail account just downloaded my whole inbox from the past three years. I have thousands of duplicate messages now. This extension says "No duplicate messages found" yeah ok.

This review is for a previous version of the add-on (0.3.17b1). 

Rated 5 out of 5 stars

I have downloaded this add on; however, when I "run" it, I am asked which program to use. Installation help, please.

This review is for a previous version of the add-on (0.3.17b1). 

Rated 5 out of 5 stars

Works like a charm for me Thunderbird 60.4.0, Win7. Love the multiple options for checking duplicates.

This review is for a previous version of the add-on (0.3.17b1). 

Rated 5 out of 5 stars

Works great for me on Thunderbird 60.4.0 (32-bit) on Windows 10. Thanks!

I've reduced my Thunderbird hard drive footprint by about half due to an enormous number of duplicates (I'm not sure what is causing these duplicates to occur. There were a huge number in my archive from 2018, much fewer in previous years).

This review is for a previous version of the add-on (0.3.17b1). 

Rated 1 out of 5 stars

Funktioniert mit TB 60.* leider nicht mehr!
Bitte updaten...

This review is for a previous version of the add-on (0.3.17b1). 

Rated 3 out of 5 stars

After updating TB, I have problems to remove my douple messages. Is there a limit in mailbox size or number of messages in the mailbox? Smaller mailboxes are running, but my box with only about 7000 mails is simply stopping the TB and i have to restart. Prior to the update i had two Add-ons, which have done the job properly. Now I would be happy to learn how to fix it.

This review is for a previous version of the add-on (0.3.17b1). 

Rated 5 out of 5 stars

Works!

This review is for a previous version of the add-on (0.3.17b1). 

Rated 5 out of 5 stars

Compliment !!!!!! fantastic devoleper

This review is for a previous version of the add-on (0.3.17b1). 

Rated 4 out of 5 stars

Works as advertised. Though … "Delete to Trash" means to Local Folders trash, not the account's trash. Also could do with an update to screenshots.

This review is for a previous version of the add-on (0.3.17b1). 

Rated 1 out of 5 stars

Totally useless to remove duplicates from sent folder "! Not searching special folders"

This review is for a previous version of the add-on (0.3.17b1). 

Rated 5 out of 5 stars

Enfor, to acquire the add-on, right click on the download button (not left click as you would for a normal download. This will give an option "Save link as". Then save it to a folder on your computer i.e. Download where you will remember it. Then go into the Add-on page for Thunderbird (or whatever program you are trying to add this to. There will be a gear icon near the top right of the page. Click on that and selct Install add-on from file. Then tell it the location where you saved it.

This review is for a previous version of the add-on (0.3.17b1). 

Rated 3 out of 5 stars

I am using this add-on on one computer, but when I try to download it now (tried on several computers) I get a message that says the file is corrupted and it will not download. ???

This review is for a previous version of the add-on (0.3.17b1). 

Rated 4 out of 5 stars

From the perspective of the user already.
Thank you for your answer and I am looking forward to the next version.

This review is for a previous version of the add-on (0.3.16).  This user has 2 previous reviews of this add-on.

Rated 4 out of 5 stars

Unfortunately checkboxes for keeping messages still don't show up in the newest 0.61 version with my Thunderbird version of 52.8.
Otherwise it seems to work fine - finds duplicates across many folders.
A fix would be great, because now I have to delete the found copies manually in the folders.

This review is for a previous version of the add-on (0.3.16). 

Rated 5 out of 5 stars

I was saved by this plug-in saving my time.
Recently, it became TBver 60.0 b 6 and it could not be used
Because it was painful, self-responsibility, but were available to change the ".rdf".
It is use in win10 1803.
I carried out the mail about 20,000, but it ended before I finished writing this review.
Since multiple folders are also distinguished more precisely than each folder, they are always being rescued.
Thank you.

This review is for a previous version of the add-on (0.3.16). 

Rated 2 out of 5 stars

I played a lot with the settings and unfortunately I found still a lot mails as duplicate. They were the same, not attachements. Quite easy to find them even by eye. No idea why the settings don't work.

In some setting-cases the JavaScript stopped the work. Maybe it's my big postbox with ~10.000 mails (there are surely and easily much bigger possible) which is merged by some postbox versions which lead to duplicates or quadruplicates.

Then I tried the xpi-addin from Thorsten (which is warned as not compatible to current Thunderbird version). It serves more information and it's much more precise - AND it found all duplicates. Unfortunately you cannot resize the windows.

So my recommendation is - ask for the code of Thorsten and recode it for current thunderbird versions.

This review is for a previous version of the add-on (0.3.16). 

Rated 5 out of 5 stars

I don't know what I would do without this!
The only improvement that would be really good is the option to "Keep" (prioritise) messages that have been replied to. That way they could remain part of a long discussion thread & not break in the middle if I've chosen the wrong one.
How do I give you money? (No PayPal link on the Add-ons page).

This review is for a previous version of the add-on (0.3.16).  This user has a previous review of this add-on.