Windows 7 computer

Windows Live Mail 2012

Email address = @outlook.com account (not preview acct.)

Every single received message contains a yellow banner at the top that says:

"unknown sender  Delete and block  Allow Sender"

It does not matter if we Allow a sender the same sender and ALL SENDERS still show up this way.

Tried repair options on WLM 2012 did not do anything.

How can we fix this?

Please do not suggest pop or imap as we have no intention of not being able to sync calendar and contacts.

JF