Dim tw As System.IO.StreamWriter = System.IO.File.AppendText("C:\NUL.txt")
The above statement will generate error like: "Filestream will not open win32 devices.... don't use \ "\\\.\\\" in the path"
Reason and Rectification:
Avoid using "CON" or "NUL" like filenames as they are reserved windows device names, you cannot use such words within a filename.
