mails get flagged in OutLook

[Mathias M.]

On Mon, Feb 09, 2026 at 05:53:33PM +0000, Nuno Silva via Mutt-users wrote:
> >>     On Monday, February 9, 2026 at 09:53:53 AM MST, Matthias Apitz <guru at unixarea.de> wrote:  
> >>
> >> I'm adding to all my mails sent with mutt (like this one) two X-header
> >> lines:
> >>
> >>     X-Operating-System: FreeBSD 14.0-CURRENT r1400094 (amd64)
> >>     X-message-flag: Mails in HTML will not be read! Please, only plain text.
> >>
Why? 

No one, except spam filters, read those. Also `X-message-flag` seems to
be some Microsoft nonsense to begin with.

And as much as I support the notion of text only emails, the reality is
just different. Pretty much everybody sends out HTML mails.

So just put this in your mailcap:

text/html;w3m -dump %s;nametemplate=%s.html; copiousoutput

and this in your .muttrc:

auto_view text/html

And voila!

> This seems to be displayed by at least Microsoft MUAs, so that's
> probably why it's being used.
> 
> 
> I don't speak German, but this has a screenshot:
> 
> https://www.msxfaq.de/exchange/clients/xmessageflag.htm
> 
> -- 
> Nuno Silva
> 

That content is ancient and in times of Office365 no longer relevant.
But thanks for the nostalgia. It's been a long time since I've seen
Outlook 2007 screenshots 😀

Regards,
Mathias

-- 
Everything will be just tickety-boo today.