An often-overlooked task after the initial setup of a virtual machine (VM) running the Windows guest OS is installing the optional Virtual Machine Additions. This indispensable package provides several key benefits, including improved performance of the guest OS, integrated use of the mouse, optimized video drivers, and time synchronization with the host. For Virtual PC, shared folders, drag-and-drop capabilities, and clipboard sharing are additional productivity enhancements available.

All these features aren't native to the guest OS, however. For better integration and optimal performance, installing Virtual Machine Additions is essential. Setup is a manual process and can only be executed when the guest OS is powered up and running. For Virtual Server, locate the desired VM, then click Virtual Machine Additions under the Configuration section, followed by Install Virtual Machine Additions. To do this with Virtual PC, choose Action, then Install, or Update Virtual Machine Additions from the drop-down menu. Under Windows, the setup program will start automatically; follow the on-screen instructions to complete the installation.

With the release of Virtual PC 2007, Virtual Machine Additions has also been upgraded to version 13.883. Virtual Machine Additions is binary compatible on both Virtual PC and Virtual Server, and it's always best to install the latest version on all guest OSs. Doing so ensures the best possible experience when a VM is executed on either platform. Note that installation of Virtual Machine Additions on the host OS isn't required and will actually degrade overall system performance if applied.

To retrieve version information for Virtual Machine Additions in Virtual PC, highlight a running VM on the main console, choose Action, Properties, and review the General tab. For Virtual Server, simply go to the VM status page and locate Virtual Machine Additions under the configuration section.

Within a guest OS, use the Add/Remove Programs applet, navigate to the Virtual Machine Additions entry, and select Click here for support information--another method that works under both platforms.