A method for bridging between virtual applications and an operating system of a host computer. The method comprises retrieving virtual applications and settings of the virtual applications assigned to a user logged onto the host computer, wherein each of the virtual applications includes the following files: a virtual engine, a user data file, and an application-on-demand (AOD) file; downloading shadow files of the virtual applications assigned to the user; integrating each of the virtual applications with an operating system shell of the host computer; and causing a virtual application to be executed over the host computer when the virtual application is launched by the user.