LSASS.exe spoils Windows Live Messenger Experience

Greetings,

The last time I installed Live Messenger was a few months ago.

I installed it today and the same problem occurs. After logging in, (or
during the logging in final process before it gets to load your contacts),
LSASS.EXE goes to 100% CPU usage and nothing can stop it apart from ending
the Live Messenger task from the Task Manager.

For a 13kb program, LSASS is very annoying. I have checked and am not
infested with any Sasser or other virus.

Is there anything one can do?

Regards and thanks in advance.