Microsoft changed the default offset for volume creation to 1Mb (2^20 bytes) a while back, around Win7(? SP1)/2012R2 or so. 2^20 bytes lines up with any known

Microsoft changed the default offset for volume creation to 1Mb (2^20 bytes) a while back, around Win7(? SP1)/2012R2 or so. 2^20 bytes lines up with any known disk sectoring at the expense of "wasting" 1 mb, which wrt today's capacities is trivial. If you want to declare a smaller offset, you can, but absent an explicit value, one (binary) mb is what you get.