How to get rid of winmail.dat attachments when using Office365 and Outlook 2016

Sometimes Outlook 2016 decides to send the body every email as a winmail.dat attachment. This works fine when the person you are sending the email to is using Outlook. But other mail users will get a blank message with a winmail.dat attachment that they can’t open.

This frustrating problem can be fixed by doing this:

1. Login to office365 as an administrator
2. Click the Admin Icon
   
3. Expand the Admin Centers Menu, and click Exchange
   
4. On the left, click “mail flow”, then click “remote domains”, make sure “Default, *” is selected, and click the Edit Pencil icon.
   
5. Edit the settings with arrows, and click Save.
6. Enjoy