Also, in usage, emails are much more treated like documents than like web pages. Well, Internet Explorer only displays HTML and the functionality of the Outlook editor was rather limited. Why didn’t they choose Internet Explorer or Outlook? With Outlook 2007, and continued in all later versions, they decided to get rid of both Word and Outlook as the email editor and replaced it with a single completely new and revamped editor (with Ribbon support!) based on Word. When you had Word as the email editor it used the Word engine to generate HTML and offered Word composing features. In previous versions, Outlook displayed the emails with the HTML rendering engine from Internet Explorer and when you had Outlook as the email editor, it used its own (limited) engine to generate it. Since the change, Outlook now only has to support 1 email editor (HTML engine) which makes developing a lot easier and you’ll get a much more consistent behavior which increases your email experience. Well… maybe they do, but not when it comes to Outlook though. Now of course the Outlook developers at Microsoft didn’t break it because they like to break things. This guide has been slightly updated from the original, which was published in September 2007, to also take Outlook 2010, Outlook 2013 and Outlook 2016, Outlook 2019 and Microsoft 365 into account. So what is this really all about? Well, to put it short because it breaks some stuff… But really, trust me, it’s not completely a bad thing that it does so.

There had been quite some fuss about this before its release and again before the release of Outlook 2010. Starting with Outlook 2007, Outlook uses only the Word engine to display and create HTML-formatted emails.

Outlook html formatting issues