It is the first thing you need to fix the issue as stated above. For that, you need to run the virtual machine showing the error and go to the Devices > Install Guest ...

If you get the Failed to create a proxy device for the USB device error when you try to connect an external USB hardware when running a virtual machine in VirtualBox ...

Late on Friday, December 13, Valve released the first public version of SteamOS. As you would expect, SteamOS is currently very rough around the edges -- it is essentially just a version of Debian 7.1 ...