The serialization enabled by this method has a series of limitations. This is because the serialization enabled is explicitly run-time, and does not have access to possible design-time information in the original XAML (if any). For details, see Serialization Limitations of XamlWriter.Save.
Calling Save is not permitted when running in partial trust.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)