New Thunderbird - mail merge


are you serious?

Change: Attachments

There is an important change in the way (individual) attachments are specified in the Mail Merge Dialog:

In Thunderbird 78 / 91 it was necessary to specify the filepath and filename, e.g. “C:\Path\To\Files\MyFile.pdf”, in the field “Attachments” in the Mail Merge Dialog. See: Screenshot

In Thunderbird 102 it is necessary to specify the filename, e.g. “MyFile.pdf”, in the field “Attachments” in the Mail Merge Dialog. Additionally you must select the files to be attached via the button “Browse”. See: Screenshot

This change is caused by a limitation of the new MailExtension APIs.

Why? Now I cannot send my mail anymore with different attachments? Who is making a new software worse instead of better?

Do I not get anything important or is it really the case that I cannot attach different attachments to different emails?

What do you mean you cannot send your email with different attachments? Maybe the new way the have created the software is different but you can do so. I use cvs to send my multiple emails and what I did is to create {{Attachment}} and below it {{Attachment1}} you can send different files to multiple users, I don’t know if you need many to send but this is the way I do it

To answer Josedky’s question, I think the OP meant that before the ‘upgrade’ it was possible to create a few files and then send a lot of messages without any user interaction between creating the files and sending all the messages. Now it appears (at least to me and the OP) that for each message sent some operator interaction is required.

If this is not the case, please enlighten us.

If it is, I’m looking for a different mail client.

I’m with the previous poster. I just tried to do a mail merge where each attachment is individualized using the recipient’s last name in the file’s name. So I was expecting to point to each file with the variable {{LastName} to attach the correct file. So, now that no longer works? I’m using mail merge to same me time when sending out graded papers for my students.

But if this no longer works, I’ll have to start looking for another email client after using Thunderbird for well over 20 years. What a shame.

I think you are talking about the Add-on “Mail Merge”.

Please address any problems to the author, Alexander Bergmann,

I think there may be some misunderstanding here. The files selected for attaching are all those that can be added to the emails. The {{Attachment}} field of the CSV/Excel designates which of those files gets attached to each individual message.
So: the selected files are your pick-list, from which the {{Attachment}} field selects the one required for each email.
It takes a bit of thinking about!
Hope this helps.

On macOS Big Sur, Thunderbird 115.4.2 does not work with Mail Merger 10.3.0
The attachments function seems unable to reach the excel file address and cannot display the number of files to send.

I confirm on MacOS Big Sur version 11.7.10, Thunderbird 115.4.3 and Mail Merger 10.3.0 , it is not possible to send attached file with a CSV or Excel file. Mail Merger seems not to be able to get the attached files to send.

It wasn’t clear how to do this, but I figured it out.

Use case: I have a number of PDF’s and email addresses.
address_1 should receive a personalised mail with attachment PDF_1,
address_2 should receive a personalised mail with attachment PDF_2,
and so on.

Addresses and other fields, including the filenames of the PDF’s are all in a csv, one set per line.

The reason for using Thunderbird with Mailmerge is that I need to pause between each mail, as our provider only allows 10 mails per 5 minutes, i.e. one every 30 seconds.

Somewhere down at the bottom in the Mailmerge help, it says this:

Attachments: (Individual)

Individual Attachments, i.e. attachments which are different for every recipient, can be added in the field “Attachments” in the Mail Merge Dialog via variable(s). Multiple individual attachments can be separated by line breaks. […]

In Thunderbird 102 / 115 it is necessary to specify the filename, e.g. “MyFile.pdf”, in the field “Attachments” in the Mail Merge Dialog. Additionally you must select the files to be attached via the button “Browse”.

The trick here is to select ALL the files that you need to attach, and to specify it’s column header in the box below in, eg. {{PDF_name}}.

Using TB 115.6.0 (64-bit) in Windows 11
Mailmerge Version 10.4.0 (december '23)

As it took me a few hours of trial and error, I hope it’s useful.

Its not possible for me to upload a full description but I use e.g.


for the first week


for the second week.
to send individual attachments.
Use browse to select all pdf files and mail merge will select the correct one.