Thunderbird: Remove Duplicate Mails

Remove Duplicate Messages is a Thunderbird extension that scans Thunderbird's email storage to find and fix duplicate messages.
Duplicate mails can be a problem even in the most advanced or modern email application. It does not matter if you use Outlook, Thunderbird, a web mail service, or a self coded mail program, duplicate mails can be a problem in each program.
This can happen for instance if you merge folders in a mail program or if a server error or download error results in multiple downloads of the same email from the mail server.
Remove Duplicate Messages

The Remove Duplicate Messages extension for Thunderbird provides you with options to remove those duplicate messages in the mail client.
Just right-click a folder in Thunderbird after installation of the extension and choose Remove Duplicate Messages from the context menu. Mails can be sorted by information such as sender, messageid or subject.
A test run on my main computer had the result that it did show more than 1000 duplicate messages. I thought that this was an error at first but it was not. The extension marks one mail with the keep flag and all other mails that are duplicates of it with the DEL flag.
A left click on a mail opens the containing folder of it, a right-click a small popup window with the most important details of the selected mail.
Oh, and guess what. Deleting those 1000 mails reduced the size of all mailboxes by more than 60 Megabytes.
You may want to open the preferences of the extension after installation first, as you can configure several important features there.
The main settings tab for instance lists all the parameters that the program uses to find duplicate email messages in Thunderbird. That's the message ID, the data in seconds, the subject and the from address.
You can add more parameters there, or remove existing ones. The additional parameters made available are date, line count, message body and the to address. The author notes that the scanning slows down if the message body comparison option is enabled in the preferences.
The second settings tab lists additional options. Here you can define which email you prefer to be deleted, e.g. the first found email, the larger or smaller email, or unread or unanswered amils.
While I would not recommend using it, it is possible to enable auto delete here so that duplicate emails get deleted by the program automatically. This can work out well if you limit the comparison metrics to message ID for example, but is generally not advised.
Verdict
Remove Duplicate Messages is a useful extension for Mozilla Thunderbird that enables you to scan mailboxes to find and deal with duplicate messages.






You said that Outlook isn’t your main email client, so which is your main one?
I think its thunderbird
It is Mozilla Thunderbird.
Awesome! This actually solved my problem… what a stupid bug.
If this is the same bug that I’ve encountered, there may be another fix: (1) hover over open Outlook item in Taskbar, cursor up to hover over Outlook window item, and right-click; (2) this should give you Restore / Move / Size / Minimize / Maximize — choose Move or Size; (3) use your cursor keys, going arbitrarily N/S/E/W, to try to move or size the Outlook window back into view. Basically, the app behaves as though it were open in a 0x0 window, or at a location that’s offscreen, and this will frequently work to resize and/or move the window. Don’t forget to close while resized/moved, so that Outlook remembers the size/position for next time.
THANK YOU Claude!!! I could get the main window to launch but could not get any other message window to show on the desktop. You are my hero!!!!
Solved my issue! 6 years later and this is still problem…
Fantastic. Thank you. Size did the trick.
This solved my Outlook problem, too. Thank you. :)
Thank you so much, this started happening to me today and was causing big problems. You are a life saver, I hope I can help you in some way some day.
You are a god – thank you!
thanks a lot…. work like charm.. :-)
Yah…thanks Claude. I’ve been having the same problem and tried all the suggestions…your solution was the answer. It had resized itself to a 0/0 box. Cheers
Excellent post. This had me baffled even trying to accurately describe the problem. This fixed it for me.
Thank you
Thanks a lot for the article. Don’t know why it happenend, don’t know how it got fixed, but it was really annoying and now it works :-)
Thanks a lot. I was facing this issue from past 3 week. I tried everything but no resolution. The issue was happening intermittently and mainly when I was changing the display of screen ( as i use 2 monitors). The only option i had was to do system restore. But thanks to you.
I’ve been tried to sole this problem for 12hours. Your comment about changing the display of screen helped me a lot!! Thanks!!
Thank you…don’t know why this happened but your instructions helped me fix it. Running Windows 10 and office pro 2007
Great tip! Thanks!
Worked for me, too – thank you!!!
It’s Worked for me, too
thank you very much!
I had a similar issue with Outlook 2013 on Windows 10 and this helped me to fix it. Thank you very much!
Thank you so much. Solved!
Considering you published this in 2012, incredible not been debugged by Microsoft.
Thank you again. M
This problem was faced by only one user logging to TS 2008 r2 using outlook 2010.The issue was resolved.
Thanks.
Great tip. Thank you!!!! If it helps, I had to use the Control Key and the arrow keys at the same time to bring my window back into view. Worked like a charm.
Thank you, this worked !!!!
Man, you are a fucking god. Thanks a lot, what an annoying bug!!
Awesome, this post solved the issue. Many thanks!