Microsoft FTP Service Default Behavior!

On Microsoft FTP server when there is a folder named after the logged in user in the defined FTP root folder then once the user has logged in, it jumps to that folder automatically. This is what I knew from some time ago but some days ago I made a new discovery! When there is no relevant folder to the logged in user, Microsoft FTP service does not give up easily and looks to see whether it can find a folder named "default" and jumps to that directory if it is located in the FTP root folder! I am not happy with these undocumented behaviors and I couldn't find any answer on how to change these defaults.