The first time you run Viscosity it will ask you for the username and password of an account with administration rights on your computer (in most cases this is your normal account).

Viscosity requires special permissions to be able to function correctly. By entering your username and password you are giving Viscosity temporary administration rights so it can setup these permissions.

These permission changes include modifying the execution rights on several files inside the Viscosity application bundle, as well as lowering the rights on several files to protect them from malicious users. Viscosity requires these extra permissions to load/unload the TUN/TAP drivers, create OpenVPN tunnels, and modify routing and DNS settings.