Saab,
It applies to those using Outlook to manage their mail on their desktop.
I don't use outlook.com, so I don't know if it applies to that.
I have done what they said, but can't find the right way to direct mail to what always used to be my inbox. So I now have my "old" inbox, that worked perfectly well, and a new inbox which is not as intuitive as the "delete" instruction no longer works, - which was the press of the delete key - I have to use the "purge" instruction from the drop down list. The delete key now just puts a line through unwanted mail, or stuff I do not want to keep. I then have to purge it.
This new arrangement also delivers all the crap to my desktop that used to stay in the (BT) server in Junk e-mail.
It wasn't broke - why "fix" it??