Whereas in Outlook for example, we create GROUPs which is basically a list of addresses, so that we can just specify a group name in an outgoing mail and Outlook will expand it into a list of receiving email addresses.  In Windows Live Mail, the feature disappeared, replaced by a thing called “Category” which is similar.

 

There is a bug with Category feature in Windows Live Mail.  Frequently Windows Live Mail fails to expand a category properly, resulting in a number of situations ranging from empty list - no email addresses – one or some of the address on the list.   When errors are spotted, I would exit and then turn on Windows Live Mail again.  Eventually it will work properly, but even then, it – category expansion - may work perfectly only for most but not all categories.