On Windows you'll need to install a make-shift CDC driver for the GridSeed ASICs. This is basically an unsigned, hand-crafted INF file that allows Windows to recognize the device properly.

Note that, depending on the version of Windows, you'll need to Google steps that let you install unsigned drivers.

https://www.dropbox.com/s/w06b7nj1f07lv29/Windows_ASIC_CDC_Drivers.zip