Unable to write to a text file (Windows Universal) in c# using File.WriteAllText();

Question

I'm trying to do a very VERY basic operation:

    public async Task WriteAsync(string path)
    {
        // Write to text file

        try
        {
            lines = "Hello, World";

            File.WriteAllText("Assets\\Write.txt", lines); 

        }
        catch (System.Exception e)
        {
            lines = e.Message;
        }
    }

I am getting the following exception:

{System.UnauthorizedAccessException: Access to the path '.......AppX\Assets' is denied.

at System.IO.Win32FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, FileStream parent)

at System.IO.Win32FileSystem.Open(String fullPath, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, FileStream parent)

at System.IO.MultiplexingWin32WinRTFileSystem.Open(String fullPath, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, FileStream parent)

at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options)

at System.IO.File.InternalWriteAllText(String path, String contents, Encoding encoding)

at System.IO.File.WriteAllText(String path, String contents)

at SynSent18.KnowledgeBase.d__8.MoveNext()}

I have Assets set to Everyone full control. I have even attempted to pre-create the file in Windows and give THAT full control. The error persists.

Ideas?