C# WinApp System.IO.Directory.Move แล้วขึ้น Error Source and destination path must have identical roots. Move will not work across volumes.

private void Form1_Load(object sender, EventArgs e)
        {
            string path = @"C:\1\2\3\4\5";
            CreatePath(path);
            System.IO.DirectoryInfo di = new System.IO.DirectoryInfo(@"D:\1311");
            di.GetFiles("*.*")
                .ToList()
                .ForEach(f =>
                       {
                           f.CopyTo(System.IO.Path.Combine(path, f.Name));
                       });
            string _path = @"C:\5\1";
            CreatePath(_path);
            System.IO.DirectoryInfo _di = new System.IO.DirectoryInfo(path);
            _di.MoveTo(_path);
        }
         void CreatePath(string _path)
        {
            if (!(System.IO.Directory.Exists(_path)))
            {
                System.Diagnostics.Process.Start("cmd.exe", "/c md " + Convert.ToChar(34) + _path + Convert.ToChar(34));
            }
        }