Email text extends to right margin

[andwhatthen]

Well actually I switched back to the new toolbar from classic, and it's still ok. So I'm not sure what triggers the right side cutoff but switching toolbar styles seems to fix it.

Hm, been 8 years now ... No matter which layout style I use (classic, wide, vertical), some emails display the text all the way to the extreme right. I'm on ThunderbirdPortable_52.4.0. I also tried the 'Message body as' option but still fail. Any solution?

[DanRaisch]

How was the message sent to you, as plain text or as HTML?

[andwhatthen]

How was the message sent to you, as plain text or as HTML?

Not sure how to tell. Have no contact with the sender. It's an automated email. How can I tell on my end?

[DanRaisch]

Is there any colored text, bold font, or images displayed in the message?

Try menu path Tools=>Options->Advanced->click on the "Config Editor" button.
Enter "wrap" (without quotation marks) into the Search field.
See if "mail.wrap_long_lines" is set to true. If not, double click on that entry to toggle it to true.
See if "plain_text.wrap_long_lines" is set to true, If not, double click on that entry to toggle it to true.\
Check the value for "mailnews.wraplength". If greater than 72, right click on that line, select "Modify from the context menu and lower the value. Click on "OK".

[andwhatthen]

Is there any colored text, bold font, or images displayed in the message?

Try menu path Tools=>Options->Advanced->click on the "Config Editor" button.
Enter "wrap" (without quotation marks) into the Search field. See if "mail.wrap_long_lines" is set to true. If not, double click on that entry to toggle it to true. See if "plain_text.wrap_long_lines" is set to true, If not, double click on that entry to toggle it to true.\ Check the value for "mailnews.wraplength". If greater than 72, right click on that line, select "Modify from the context menu and lower the value. Click on "OK".

Thank you for the reply and effort. Appreciated.

Yes, there is coloured and bold text in the emails, which display wrong. I just checked in https://outlook.live.com/owa/ and that very same email displays correctly there.

Worth noting that it's not all emails, containing colour and bold text, that are displayed wrong. Can't tell what the patter is. When I say emailS I'm referring to 2 emails that I discovered display wrongly. Now I can't remember which the 2nd one was but at least I have 1 that displays wrong so it can be used for the investigation. However, after browsing quite a bit thru my inboxes I did notice that 99% of the emails display correctly so I guess I can live with an email here and there which is off. Out of curiousity I do wanna get to the bottom of these 1 or 2 emails, displaying wrongly.

mail.wrap_long_lines was set to true
plain_text.wrap_long_lines was (by default) set to false and I made it true (but it didn't help)
mailnews.wraplength was set to 72 so I left it as is

EDIT:
I now have a 2nd email from another source, which also displays wrong. Worth saying that both emails are automated ones.

[DanRaisch]

As it is just those two automated messages it's likely that it is a matter of improper formatting on the part of the sending system. You've tried switching the display of the message body to each of the three options so it seems Thunderbird can not properly interpret whatever coding was used by the senders.