What happens if I apply to US colleges having attended one semester?
Unless the school and all its records were recently destroyed , seems like you owe that school some money to get that transcript, or the grades are rather embarrassing. If it is a money problem, you need to pay. If the grades are embarrassing, it is OK, you are not the first to do badly in the first semester of college. But yes, you do need to disclose all previous attendances.