I ran into that problem too, which was part of the reason for my original post. I ended up setting up a virtual machine (w/o Take Command being installed in it) and used it to install TC onto the thumb drive, and registered it with the USB key option within there. The thumb drive installation works successfully on multiple computers that I tested it with. But it still seems like an issue to have to use another computer or VM to install the thumb drive version without having to uninstall from your main computer first.