Q:  I have a DBF table that I can't open because it is expecting an MDX (production index) file.  I lost (deleted) that file.  What do I do now?

A:  Byte 28 in the DBF file header indicates whether an MDX file is needed.  (0 = no MDX needed; 1 = MDX needed.)  Here is some code that makes the change for you.  It uses a radio group where the first item is NO MDX (element 0), and the second item is USES MDX (element 1).  This app also uses the TOpenDialog component.

procedure TForm1.Button1Click(Sender: TObject);
var
  f: file of byte;
  b: byte;
begin
  if OpenDialog1.execute then
  begin
    assignFile(f, OpenDialog1.FileName);
    reset(f);
    seek(f, 28);
    b := RadioGroup1.ItemIndex; {0 = no MDX; 1 = use MDX}
    write(f, b);
    closefile(f);
  end;
  OpenDialog1.FileName := '*.dbf'; {reset the filter}
end;