HTC One M8 Windows - Not charging USB in car
My HTC One M8 with Windowsphone 8.1 did not charge in my car USB. It charges fine with the stock adapter in a wall outlet but not with my USB cable or the HTC USB cable in my car.
ANSWER: I have Windows set to popup and "Ask me before using USB data connection". I just picked "Yes" since it seems reasonable. Turns out that if you pick "Yes" and thus have a data connection, it will not charge. If you pick "No", it will charge just fine but you won't have data.
BOTTOM LINE: If you want to charge your phone with a USB connection, do not use data. It works fine in the car with the HTC cable or my generic USB cable.