Delphi NAS ForceDirectories : I cannot seem to be able to ForceDirectories on a NAS partition with Delphi.
I can create a folder on the NAS with Windows explorer fine.
Code is:

        procedure TForm3.Button1Click(Sender: TObject);
    var
      tempDir: String;
    begin
      tempDir := 'z:\ttt\ttttest';
      if NOT DirectoryExists(tempDir) then
        if System.SysUtils.ForceDirectories(tempDir) then
          ShowMessage('Dir: ' + tempDir + ' Forced alright')
        else
          ShowMessage('Dir: ' + tempDir + ' Force FAILED with error : '+ IntToStr(GetLastError));
    end; 
Z: is the Western Digital Network Attached Storage which works fine in all other respects.
The code returns error 3 every time.
Same code works alright on local drives.
Delphi Seattle, Windows 10 64 bit.