Windows 10 reached EOS (end of support) on October 14, 2025. If you are on Windows 10, see this article.

Mozilla サポートの検索

サポート詐欺に注意してください。 私たちはあなたに通話やショートメッセージの送信、個人情報の共有を求めることはありません。疑わしい行為を見つけたら「迷惑行為を報告」からご報告ください。

詳しく学ぶ

このスレッドはアーカイブに保管されました。 必要であれば新たに質問してください。

Mails composed as HTML is sent as plain text if it does not contain any formatting

  • 2 件の返信
  • 4 人がこの問題に困っています
  • 131 回表示
  • 最後の返信者: behoocco

Since one of the lase TB versions HTML mails are sent as plain text, but only if no formatting is applied. This is a problem because for plain text mails I configured line wrap. So lines are wrapped unexpectedly. A suitable workaround is to add a bold space character, but sometimes I forget.

This is the header of such a mail:

User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101

Thunderbird/52.5.0

Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Language: de-DE MIME-Version: 1.0

Since one of the lase TB versions HTML mails are sent as plain text, but only if no formatting is applied. This is a problem because for plain text mails I configured line wrap. So lines are wrapped unexpectedly. A suitable workaround is to add a bold space character, but sometimes I forget. This is the header of such a mail: User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Language: de-DE MIME-Version: 1.0

選ばれた解決策

What setting have you got under your 'Send options' ?

Menu icon > Options > Options > Composition > 'General' tab click on 'Send Options' button. See image below.

Please post image of your settings.

この回答をすべて読む 👍 1

すべての返信 (2)

選ばれた解決策

What setting have you got under your 'Send options' ?

Menu icon > Options > Options > Composition > 'General' tab click on 'Send Options' button. See image below.

Please post image of your settings.

Thanks a lot!

Unselecting "send message as plain text if possible" solves my problem.

I suppose is a new option with a non backward compatible default setting (selected). I never noticed it before and did not observe messages being sent as plain text when composing as HTML.