I bumped this thread, just to make something clear:
http://shoutbox.menthix.net/showthread.php?tid=78...d=865483#pid865483
In the above thread, you will see what the real problem is. I don't know if this has been fixed in 4.50 because I still avoid creating such an -only sound- notification for people sign-in (indeed I didn't read anything about this bug in Changelog, maybe there is nothing to fix for Plus! side of the bug]. If you still continue having this problem, disable the event ntofication you have set, or edit it like that it will also show a toast to you (this kind of notification has not been reported for any problem), if you do this second thing, you may want to disable Windows Live Messenger's own sign-in toasts in order not to see two toast windows for each contact signs-in.
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