Some VPN clients like Cisco has the option set by admin to disconnect all external network connections except the active VPN connection. This makes the user part of the corporate network but also disallows any connections to local machines or devices like printers. What if you ran a virtual machine? You can set up a virtual machine that is connected to a VPN but the native OS can be left untouched.
ExtremeTech used this kind of method because someone’s VPN client was not compatible with Vista and so they installed a XP VM which would be used to connect to a VPN.