Works great and ultra fast too! Rated 5 out of 5 stars

Impressive, the (Alternate) version I tried did nothing. However this add-on functioned exactly as expected -and- the results were instantaneous! HIGHLY RECOMMENDED

BTW, the review below (entitled-"Great with one annoying limitation") is in complete error. This add-on easily lets you choose whether you want to use MessageID for comparison purposes or not.

Saved my biscuits Rated 5 out of 5 stars

I had some massive duplication in two folders. Really bad. I discovered this. Ran into some limitations with T-Bird and how it handles trash. Ran into some slowdowns but, as I said in the title, it save my biscuits, or however you want to say it, it saved the da. I broke the mailboxes down into digestible chunks and than ran this on each one, then reassembled them. Thanks. If it were donation-ware, I'd donate 5 bucks, but I could not find a link.

Great with one annoying limitation Rated 2 out of 5 stars

Unfortunately I have many duplicates that are absolutely identical except for the messageID. THis addon does not allow comparisons of messageID's so is only of limited use to me.

erratum: runs on 45.2 as well Rated 5 out of 5 stars

just tried to run it on 45.2 and it detected duplicates. thanks

This user has a previous review of this add-on.

Great addon. Had one message cause it to hang. Rated 4 out of 5 stars

I used this addon to sort through years of backups to reduce them to a set of email without duplicates. Worked great except: It would hang and I finally found the one message that caused it. I need to submit a file to be checked as to why.

Funktioniert einwandfrei (45.1) Rated 5 out of 5 stars

Mal eben in wenigen Sekunden ein paar 10000 Mails gelöscht. Vielen Dank für dieses praktische Plugin!

great add on ...but Rated 4 out of 5 stars

Work only one time when just installed in 45.1. Does not work when Thunderbird is shut down and reopened. To get it work I have to uninstall the module and process a fresh install on each thunderbird restart, which is a bit tedious ;)

Works faultlessly in Thunderbird 45.1 Rated 5 out of 5 stars

Thanks so much for this, Thorsten.

Does not work with TB 45.0 Rated 4 out of 5 stars

It does not work with Thunderbirt 45.0. Before it works qiute well. Could you make it work again, please?

Loaded Thunderbird to use this add-on Rated 3 out of 5 stars

Decided to give Thunderbird a try because I found out about this add-on which would, hopefully, allow me to clean up my inbox. However, in looking at the configuration, one of the simplest and most common sense options would be to delete OLDEST duplicates... but, instead, it only allows for "first found". Am I missing something in the way this is worded? Please help... I would LOVE to be able to utilize this extension.

Very useful but buggy Rated 4 out of 5 stars

Very powerful, you need to review the available options. Annoyingly, the most important feature for me, which is to be able to select in each case which of the duplicate messages to preserve, it doesn't work (Win 10) but gives a javascript alert instead, e.g. "Author: "" <>nSubject: Save $10 When You Shop Early at Amazon.canMessage URI: mailbox-message://nobody@Local%20Folders/To-Be-Checked/2004#123836379nFolder URI: mailbox://nobody@Local%20Folders/To-Be-Checked/2004nMessage format: mailbox-message"

Can not toggle Rated 3 out of 5 stars

The extension is good. I had no problems even in a folder with 12000+ emails. The only problem is that I can not toggle between DEL and KEEP. My mouse is a standard 2 button windows mouse and have no "middle" button. Even the button on the scroll is not working.

Another reason not to use it Rated 1 out of 5 stars

I tried it on a different inbox after compacting the folder so that the index was valid. I got the same result - all e-mails older than two weeks were removed.

It works better on some sub-folders but its ability to recurse into sub-folders seems sporadic. Sometimes it does and sometimes it doesn't. I have no idea why.

And I've got some subfolders that have duplicate messages that it identifies and says it will remove but doesn't. While not dangerous the way its behaviour on the inbox is, it's also not useful.

This user has a previous review of this add-on.

Great Add-On Rated 5 out of 5 stars

works fast and perfect!

OK , but Rated 4 out of 5 stars

Version 0.1.13, Great, 5 star . Version 0.1.14 OK to a point. Small number of emails to compare, works. Large number of files to compare, it hangs!! Was comparing a folder with 4852 emails.
Hangs. Hope 0.1.14 gets fixed. {Using Thunderbird 38.2.0} on Win 7.

Rated 5 out of 5 stars

Hatte neulich Stress mit dem Synchronisieren, so dass hunderte von Nachrichten querbeet doppelt waren. Mit diesem Addon ratzfatz erledigt.

Small problem Rated 4 out of 5 stars

I've unchecked the sent box and it still won't delete or even find duplicate sent messages. Any ideas?

Rated 3 out of 5 stars

It finds dupes and is fast about doing so, but the documentation is almost nonexistent. It is impossible to toggle a message between keep and delete In Windows 7 / TB 31.2.0 / add on version 0.1.14 .

There is no support channel and the add on doesn't play nice with Thunderbird.

If all your messages are in one big folder and you want to run something once to clean up dupes then this will work for you. Otherwise it is of limited use.

TB 31 bug ? Rated 3 out of 5 stars

I learned by trying out that the add-on works in TB 31 once you restart TB.

This review is for a previous version of the add-on (0.1.13).  This user has a previous review of this add-on.

Love and Debug Information Rated 5 out of 5 stars

Everyone knows this is the most important must-have add-on for Thunderbird, but recently I'm having a little issue with TB 31 series.

It seems that for some mailboxes, the plug-in gets a return count of messages in the mailbox that is incorrect, and that leads to some deletion errors. In some cases, the message-count is even zero, which makes the plug-in think that there are no messages to compare and clean!

It must be the changes to some API calls in TB, similar to the way identifying a DOM id has changed, or getting the proper handle for a mailbox URI.

Or perhaps I've moved the message(s) or the plug-in has moved the messages(s) once already, or even a filter has moved the message(s), and they now have a header or TB flag on them that's not taken into account?

Does a message having been in the trash and then been taken out also affect the plug-in? That may have happened there any way to restore the status of those messages so the plug-in works on them again?

In any case, I will wait patiently as always as I know you are busy and doing your best to make it compatible with the current round of changes in TB!

Keep up the good work - your plug-in is AWESOME!!!!

This review is for a previous version of the add-on (0.1.13). 

Yes, some API calles behave different now and are marked as deprecated. Please contact me via eMail. I might have a solution
(rdm "at"