Well, that explains why, when I try to paste text into an Outlook email, I get an error "there's a problem with Word". (Then you hit Enter and paste again, which works fine.)
It's good to remember that Outlook isn't actually an email client. It was bought by Microsoft back in the days before TCP/IP became common. Outlook (still) calls messages "memos". The _first_ thing Outlook does with an RFC-compliant email is convert it into the Outlook "memo" format. There is no option to view the original email message at all. Microsoft simply bolted on a filter to deal with emails. I had hoped that the "Mail" client in Windows 10 would be a real mail user agent, but it's _worse_ than Outlook, without the excuse of predating email and being another program MS bought and rebranded.
> Only a monopoly like Microsoft could get away with that.
What's the problem there? Unless Microsoft forces you to buy a separate Word license to use their email product, who cares if they reuse some of their own code?
Because they are a monopoly, they get to ignore the HTML standards and set the defacto standard which is the subpar rendering of Word as an HTML browser.
If real competition existed senders would send modern HTML mail using CSS and Outlook would not be able to render half of it. But instead developers have to write email to the antique standards used by Word, with layout using tables and without css.
And Microsoft doesn’t care, they get away because Outlook is the monopoly.
Only a monopoly like Microsoft could get away with that.