mw.hlp (Topic list)
30796
WORD CANNOT FIND ANY LINKS TO UPDATE.
 
You chose Insert File and Update Link, but Word
cannot find any linking codes to update in the
selected text or data.
 
■ Make sure there are .D. or .L. codes and a
  filename at the beginning of the text or data
  you want to update. (Choose View Preferences to
  select the Hidden Text option.)
■ To update all imported areas at once, select
  the entire document.
■ Include the starting .D. or .L. codes in your
  selection to update a section of your document.
  Make sure the codes are formatted as hidden
  text.