It will not change anything in poser or effect poser in any way. Its really not a text file its kind of a graphics file. Once you change it you can only change it to some other type and since there really is no type its probly best to leave it like it is. Ok I kind of lied there is a way to unassociate it but its a pain in the rump to do. You have to install a program that has its own file type then asssociate it with that program then delete it from your computer.