A system and method of operating a client network computer in a disconnected mode. A client computer system includes a client storage device, a processor, a network interface, a failover server and a software manager. The processor is configured to execute software instructions stored in the client storage device. The network interface is configured to connect the client computer system to a remote network server unit. A failover server implemented on the client computer system is configured to provide functionality similar to the remote network server unit by accessing a copy of a network database file stored on the client storage device. A software manager stored in the client storage device is configured to cause the client computer system to connect to the remote network server unit if the remote network server unit is available or to cause the client computer system to connect to the failover server if the remote network server unit is not available. The remote network server unit is configured to provide a client cache image file to the client computer system. The client cache image file contains information, such as a copy of the operating system, a copy of client boot configuration files and a copy of the network database file, which causes the client computer system environment to appear to a user as though the client computer system is connected to the remote network server unit when the client computer system is actually connected to the failover server.