The Astrapi only states compatibility with iOS as far as I can tell. Am I wrong?
This is not a problem with your Z170x. I'd try connecting to USB2 only.
Thanks for the speedy feedback Shadow,
The Astrapi is plug n play on IOS, Android and Windows and the USB 2 port is being used.
As it works OK on Win 10 my guess is the problem lies with the USB drivers Gigabyte supply for Win 7. What do you think?
BTW device manager is not showing any USB 2 controllers or hubs, just 3.0 and 3.1