Organizing and accessing contact information in Outlook.com
This is a great tip! I really hope it works, for I'm also receiving several e-mails a day without sender. At least I found it interesting to see that some of them do have the same sender, but are about different topics.
Another interesting part about these e-mails -besides having no sender-, is that they all have the unsubscribe option at the bottom, but that leads to a not working page (and I'm a bit anxious as well that clicking that link is not recommendable and leads to more spam).
I really hope Microsoft will continue working on this before it makes victims...