In the second week of this month, Microsoft had alerted Windows Live Mail 2012 users that some chnages are coming to users of Microsoft accounts like Outlook, Live, Hotmail, MSN accounts that may prevent mails being delivered to Windows Live Mail 2012. And it said, in order to continue using this Mail client, you need to install this update.(Update for Windows Live Essentials Mail 2012 (KB3093594) )
Source : meraTechPort