Are your messages composed using HTML? I guess the message is being converted to plain text when forwarded.

Check that the correspondent isn't marked as preferring plain text in his Address Book entry.

You might find that holding down shift whilst clicking Forward helps. But it is not a nice solution.

The formatting is actually just whitespaces to keep my text aligned. I did not use HTML. The Content-type field in the message source is marked as text/plain. The formatting was lost even before I typed the recipient's address. The preference for the recipient was marked as Unknown in my address book.

Your suggestion to hold the shift while pressing Forward did preserve the formatting. Thank you so much for the tip. How can I make this as the default for forwards?

Your biggest issue here is that it is unlikely any of those getting your mail will see it as you think you are sending it. Most will receive it in a proportional font on a web mail browser session. In those circumstances the "lost formatting" is what will be seen even if you send fix width plain text. Most email client these days struggle with plain text as well. HTML is taking over. Like it or not.

I think you need to look at using HTML tables for your formatting. Then your recipients will stand a chance of getting what you send.

I am only sending to one recipient for this and he receives as intended but no longer does so with the new TB unless I forward as per Zenos suggestion. The mail is from an old shopping cart programme I am using and unable to do the necessary conversion in the near future. Is it possible to make Zenos suggestion the default for my forwards?

Pannir said

Is it possible to make Zenos suggestion the default for my forwards?

Your choice is all compose or not. Forward, reply and write all use the same settings.

What is the formatting that is chosen for the following action: "holding down shift whilst clicking Forward" ?

Pannir said

What is the formatting that is chosen for the following action: "holding down shift whilst clicking Forward" ?

The reverse of what is selected in Account settings > Composition and addressing for the account.

If the option is set to compose in HTML holding shift makes it not so, you get text only.

If it is not selected holding shift you get HTML composition.

In plain text composition there is no toolbar between the addressing block and the email body. In HTML you get the font and style choices on that toolbar.