If you get the message that you have reached the limit of logs with someone and it asks if you want to keep the old logs and you press Yes it opens a window to save it. This used to open up in the My documents >> My Chat Logs folder but now it doesn't. For me it opens My Shared Folder. If you then drag the window a bit you first get a new one next to the first one and if you drag that one too MSN Messenger crashes .

I think, all along, it is MSN Messenger's logging function that would tell you that your logging file size has reached its limit (8192 entries). Would you check again?