Open Outlook. Tools open drop curtain until Options appears. It rolls down on mine at the very end edge. A pain. Then click Options.
Click Mail Format Tab. Message Format section at top of tab there is a selection curtain
Check the pic below.
Check the box I circled in yelllow only.
In the curtain select HTML.
Click Okay at the bottom.
I had to do this to mine. Rich text only showed text.
Hope that takes care of it.