How to compare two Thunderbird folders?

User Help for Mozilla Thunderbird
Posts: 27
Joined: March 1st, 2009, 2:13 am

Post Posted March 9th, 2009, 5:01 am


I have two folders in my Thunderbird with nearly the same content. Is there an addon or an integrated function to compare two folders or even better to create a new folder wich includes the differences?




User avatar
Posts: 28902
Joined: August 12th, 2006, 8:27 am
Location: Middle England

Post Posted March 9th, 2009, 5:08 am

One way to achieve a similar sort of effect, would be to combine the Folders together, or make them subfolders of the same folder, then use one of these Extensions, to Eliminate all the Duplicates
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -Albert Einstein

Please DO NOT PM me for support... Lets keep it on the board, so we can all learn.

Posts: 27
Joined: March 1st, 2009, 2:13 am

Post Posted March 9th, 2009, 2:17 pm

But when I eliminate duplicates, only one of the two duplicates would be deleted, or not?

Posts: 27
Joined: March 1st, 2009, 2:13 am

Post Posted March 11th, 2009, 3:38 am

OK, I tried it in a test environment and it was working:
I created a folder "both" and created the subfolders "1" and "2". I copied the content of one of my folders (200 mails) into both folders ("1" and "2") and ran "Remove Duplicate Messages..." on the "both" folder. He found all duplicates and I was able to delete them. Fine!

But then I tried to use it like this:
I have a backup of one of my folders, let's call it "uncut" and I have the folder "cut". The folder "uncut" includes all mails which are also included in "cut". Some of the mails which exist in "uncut" where deleted from the "cut" folder. I want to know, which mails have been deleted from the "cut" folder. So I created another "both" folder and copied "cut" and "uncut" to it. When I run "Remove Duplicate Messages..." on the "both" folder, no mails are found. Any ideas why this happens? When I open mails of both folders and compare them manually, they look total identically.



Posts: 213
Joined: December 1st, 2004, 1:38 am

Post Posted November 3rd, 2009, 6:49 am

You can try the mboximport extension, export index of the folders you want to compare, then run compare using eg. notepad++ (Plugins > Compare).


Posts: 8
Joined: September 9th, 2008, 11:02 am

Post Posted September 7th, 2019, 6:56 pm

Although this is a decade old I found it and it was helpful. But here is what i did also on it.

- Thunderbird 60.9.0 (64-bit) macos
- Thunderbird 68.0 (32-bit) windows 8

-folderA - 1000 messages
-folderB - 2000 messages
-you want the 100 messages not in folderA that are in folderB

Here's how i did it.
- copy all messages from folderA and folderB put them in folderC
- download and install the following extension ... uplicates/
- second mouse button click on folderC and then remove duplicate messages
- you'll see the results of the message and the duplciates
- click "All Delete"
- click "Delete Selected"

the result will give you only the messages not in folderA.
- Copy those messages to folderA.

note: for macOS users
- I'm on a macOS
- i used http to download windows VM image to install the and run thunderbird for windows
- then i transferred the macOS thunderbird folder profile contents in the library to the windows directory where the thunderbird profile resides
- it loaded on windows just fine and processed with no effort.
- then i did the above.

hope it helps any macOS or windowsOS users that had this same issue of thunderbird not copying all the emails over.


User avatar
Posts: 39560
Joined: October 19th, 2007, 1:53 am
Location: The South Coast of N.S.W. Oz.

Post Posted September 8th, 2019, 3:37 am

Once again...
Please don't bump these very old threads.

Locking due to old age...
Ancient Amateur Astronomer
Win-7-HP/IntelĀ® DualCore-2.0GHz/500G HDD/4 Gig Ram/550Watt PSU/350WattUPS/Firefox-20.0-62.0-70.0-79.0/T-bird-
(Always choose the "Custom" Install.)


User avatar
Posts: 124982
Joined: September 23rd, 2004, 8:57 pm
Location: Somewhere on the right coast

Post Posted September 8th, 2019, 3:42 am

Thank you, but after 10 years with no activity, this doesn't seem to be a very common issue. Locking this thread due to the age of the original posts.

Return to Thunderbird Support

Who is online

Users browsing this forum: No registered users and 2 guests