re : The Send button is missing, see my screenshot.

The 'Send' / Senden is greyed out and this is normal because there is no entry in a TO or Cc or BCc field. Once you enter an email address, then the Send button becomes enabled. This is because you cannot send to nothing.

It is possible the file is being scanned before sending. Do you have an Anti-Virus product which can scan outgoing emails ? If yes, then suggest you disabled it and stop scanning outgoing emails to see if this is the cause. Please note, if you use a product which you installed eg: Norton AntiVirus, disableing it may auto enable the default one that came with the OS, so both need to be stopped. A quick way of checking is to restart The computer in 'Safe Mode with Networking' as this stops the AV working and then start Thunderbird as normal. This will allow you to test if it is causing the problem.

But fix the information I've mentioned below first.

re :The german Umlaute like ü, ä are not displayed correctly You need to ensure you are using Text Encoding: Unicode (UTF-8). It's unclear whether this is the something you have not set up in the 'external program' so Thunderbird is opened using wrong Text Encoding, but in Thunderbird this is where you set it up.

• Menu app icon > Options > General
• scroll down to 'Language & Appearance'
• click on 'Advanced' to open the 'Fonts & encodings' window.
• Set Text Encoding for incoming and outgoing to: Unicode (UTF-8)
• click on 'OK'

Also check you have this setting:

• Menu app icon > Options > General
• scroll down to bottom and click on 'Config Editor' button
• Accept the warning
• In search type: mime
• Look for : mail.strictly_mime
• If it says 'False', double click on line to change to 'True'

click on 'Close' x

Exit Thunderbird now.

re : the nsmail-xx.tmp files are not being deleted On Windows OS they are located here: C:\ Users\Username\Appdata\Local\Temp They can be manually deleted to clean up. Please delete those nsmail files. There is a known bug which seems to effect some people. I located it for you if you want to read about it.

• https://bugzilla.mozilla.org/show_bug.cgi?id=1589890

However, as code is altering, it does not appear to manifest in the beta versions, so currently this is being monitored.

Restart computer in 'SAfe Mode with Networking' and then perform the method you use to create the email and send.

Please report back on results: Running computer in 'Safe mode with Networking' mode....

Use external program and send some files via your email client - thunderbird. Did the Umlaute like ü, ä display correctly? After entering an email address in TO, did 'Send' button become ready for use?

Did email send attachment ok ? Did the nsmail temp file get deleted ?

Note: Zipped files should be saved to a suitable location first and then unzipped so suitable program can be used to open the file. PDF / .Docx / jpeg files should easily open using designated program as the extension helps to determine what program to use.

Thank you for your replies. They did not fix the issue.

Options > General > scroll down to bottom and click on 'Config Editor' -> I was looking for this as I found a couple of hits while searching for info on my problem. I did change the value as suggested but to no avail.

Also, greyed ou 'Send' / Senden-button: as you can see in the first screenshot, upper left side - there is no To:, CC: or BCC: field so I can't enter anything.

I treat it as unsolved and decided to live with it.

re :there is no To:, CC: or BCC: field so I can't enter anything.

In your image I can see 'An' and there is no email address entered. I can see 'Kopie(CC)' and 'Blindkopie(BCC)' options which you could select if required to create Cc and/or Bcc. Neither have been selected and so you cannot enter anything in those fields until one has been selected. 'Senden' is also visible but not enabled because you have not as yet entered an email address choosing to whom you want to send the email. Once an email address has been entered then the 'Send' will appear as enabled.

So, I do not understand what you mean by there is no To:, CC: or BCC: field so I can't enter anything.

Addressing info for this new version: https://support.mozilla.org/en-US/kb/addressing-email

I wrote: "...their implementation opens up an email with prefilled text and the attachment in form of a zip archive. The Send button is missing, see my screenshot." When you look at my screenshot, and I quote myself again: "...as you can see in the first screenshot, upper left side - there is no To:, CC: or BCC: field so I can't enter anything." Made a 3rd pic where I masked the irrelevant part in white. Hope that makes it clear.

Where you see a (n empty) Send field, this is after I hit Forward from that form where Send and To is missing.

The image you posted will not show a 'Send' button because it is not a 'Write' window where you compose emails. In that state you would have to click on 'Reply' or Forward' or 'Right click on email and select 'Edit as new message' to get it to open in a Write window.

The image looks like an email which you have received and you have opened it in a tab for reading. Or perhaps a file saved as eg: .eml or html which you have opened using Thunderbird, so it simply displays it as an opened email. Not an email ready for sending in a Write window.

But, it sounds like you expected it to auto open in the 'Write' window in the first place.

For example. I have a document created using OpenOffice Writer. I have created that document and saved it, but I also want to send that document to a friend. In that opened document I use 'File' > 'Send' > click on 'Document as Email' Thunderbird has now opened a 'Write' window with the document as an attachment.

Another example where I want to send a zipped folder as an attachment to a friend. I have already created a zipped folder called 'attachments_17_11_2009.zip' saved in 'My Documents' folder. In 'My Documents' folder, I right click on the zipped folder and select 'Send to' and select 'Thunderbird email' Thunderbird has now opened a 'Write' window with the 'attachments_17_11_2009.zip' document as an attachment. See image below.

I have an external program running which lets you send some files via your email client What is the program called ?