Problem installing Huawei E3131 3G modem on 2012 MacBook Air I have a Huawei E3131 3G modem and it doesn't work on latest 2012 MacBook Air. It works with older versions of OS X with USB 2.0 so it looks like the only problem is USB 3.0.
My personal experience with Huawei is that their installation app doesn't even run on a recent Mac for some reason. When I used it, I used to look into the package content to find another installation app that would actually start. If that is not the problem, please put more details.

pmjordan might be right as well as far as 32/64 bit-ness of their installation app. USB2/3 should be backward/forward compatible as per their specs as far as I know.