But, don't you think it would be very easy to modify the logical drive serial number in another USB pen drive, copy all the data and use it (a copy). Or am I missing something. The problem that this serial is a software type serial, generated by the OS and written to the drive (anyone can do that, there are little applications for that). Instead, if you use a hardware type serial number like the one that comes with HD, that's another story. I use that fisical serial for copy prevention, but, if I'm not wrong, the USB pen drives don't have such serial number, or firmware id.