Microsoft’s StyleCop analyzes C# source code to enforce a set of style and consistency rules. It can be run from inside of Visual Studio or integrated into an MSBuild project.
One of these rules is #SA1633. This rule requires that each of your files have a file header that contains a copyright XML element. Of course, you can disable this rule if you want through StyleCop settings. But just in case you have a similar rule at your work (or your own personal rule) or need to adhere to this rule, I’ll describe the situation and provide the macro below.