Note that a lot of so called 'fixes' will actually cripple stuff more, eventhough some things might seem to work at first.
(yes, there are some problems apparently with the upgrade, but many of those problems arise from (wrong) stuff people did in the past to 'fix' some other issues)
So, please ALWAYS search the official forums of Messenger Support FIRST when you want something fixed, before you attempt to do anything else:
(There are more official sites than this one though. For example http://help.live.com/)
And if the given solutions don't work, then you can always contact Live Support by mail:
This will not only fix your issue for sure, but will also tell Microsoft about the problem so they can permanently fix it in next updates. And that is exactly the major big issue with all those so called 'fixes' on the net: they do not give Microsoft the chance to investigate and fix the bugs properly.