My family has a windows xp machine that has a western digital 2 tb attached. it housed our music library. it used to be formatted as windows file system. over the past few months ive been ripping our dvd collection to my computer. i went to transfer them today but in order for me to write i needed to make it exfat as mac and pc can read and write on that. now when i plug it into the windows machine it cant read it and says it needs to be formatted. what happened as my mbp can read it but the windows machine cant. the machine has service pack 3 installed and sp2 was the requirement for exfat i thought. the reason i made it exfat is our windows machine is about 13 years old and has 1 gb ram and a single core cpu. i cant have more than two programs open. i do all the work on my mac then transfer it so i needed a file system that both OS could read. the windows machine is partially the itunes server for our apple tv.