I've been having some problems with the chat history.

Normally, the files would be named according to the e-mail (*** Email address is removed for privacy ***), but on my new laptop they're being saved with a big number instead of @hotmail.com (examplexxxxxxxxxxxxx). Now this doesn't bother me, but some e-mails ending with .number (*** Email address is removed for privacy ***) are being saved as example.96xxxxxxxxx. So Windows mistakes the .96xxxxxxxxxx as the file type, and hence I'm not able to open the logs (that are supposed to be XML files).

Any idea how to fix this? 

I can't find a way to specify that the file type is XML, or a way to make Messenger save them as @hotmail.com.