When distributing an application that uses Xceed's WPF themes, the Xceed.Wpf.Themes.dll assembly must be distributed, as well as the assemblies corresponding to the specific themes used in that application: Xceed.Wpf.Themes.Glass.dll, Xceed.Wpf.Themes.LiveExplorer.dll, Xceed.Wpf.Themes.Media.dll, , Xceed.Wpf.Themes.Metro.dll, Xceed.Wpf.Themes.Office2007.dll, Xceed.Wpf.Themes.Windows7.dll, and Xceed.Wpf.Themes.Windows10.dll. These assemblies must either be installed into the global assembly cache or placed in the same directory as your executable.
Both signed and unsigned versions of the assemblies that contain Xceed's WPF themes are available. Either version can be distributed, but please remember that signed software of any kind can sometimes cause problems because the .NET Framework or the operating system must contact an authentication server, which can in turn trigger firewall alerts, etc.
In order to install assemblies into the global assembly cache, Microsoft Windows Installer 2.0 must be used. This is the recommended and most common way to add assemblies to the global assembly cache, and it provides reference counting of assemblies in the global assembly cache, plus other benefits.
For more information in regard to installing assemblies into the global assembly cache, please refer to the "Installing an Assembly into the Global Assembly Cache" topic of the .NET Framework Developer's Guide.