public static void Main(string[] args) { // Feel free to change to C:\\Windows\ , but it might be restricted. var rootFolderInfo = new DirectoryInfo(@"..\..\..\"); Console.WriteLine(rootFolderInfo.FullName); var directoryTree = new DirectoryTree(rootFolderInfo); Console.WriteLine("{0} KB", directoryTree.GetSummedUpSize() / 1024); }