Shoutbox

Try if deleting contactcaches solves it (exit WLM first):

delete the two contact caches (folders) corresponding with your
passport in the following folders:

WinXP:
%userprofile%\contacts
%userprofile%\Local Settings\Application Data\Microsoft\Windows Live Contacts

Vista:
%userprofile%\contacts
%localappdata%\Microsoft\Windows Live Contacts

Note: first sign in will take longer than normal because it will have to fetch your contactlist etc. from server again.