My first guess is that your device is in MTP mode or in automatic USB detection mode. Now that I’ve picked up quite a few Fuzes over the past month, I have a routine I do when I first plug in.
First off, I make sure the particular USB port I want to use works with a variety of items. This eliminates the first chain of problems.
Secondly, I make sure the USB/Fuze cable is working, normally by using it with a known-good Fuze. This might be hard if you have only the one cable, but since the cable works on your GF’s machine, it’s likely not the cable.
Lastly, I connect in a way that ensures I know how the connection works.
I turn the Fuze power switch completely off, so the little dot is visible.
I hold the left arrow side of the wheel down on the Fuze.
While holding it down, I plug in the cable.
This forces MSC mode during the initial connection.
Every Fuze I’ve gotten my hands on (and, at this point, I own more than 12) has been through this, and only two have not responded to this.
My first thought would be that there is something up with your USB port, especially if the Fuze works on the USB port of your GF’s computer. I’m sure you’re plugging it in thoroughly, but maybe you can try turning off your machine and switching USB plugs around.
My second thought is that something is up with the cable, and that you’re putting it in a different position when using your computer than when you’re using your GF’s computer. If there’s a broken wire in it, that could cause it to give that inconsistent reaction.
Of course, it’s really impossible to know exactly what you are doing unless you post every little step. All I can do is try to rule things out. I shouldn’t even assume that you and your GF are using the same operating system, which is a useful detail to know.
