That indicates your document is missing a font. Go to Type>Find Font and you'll see the font(s) that are missing.
Thanks a lot Mikey. What I don't understand, it shows me two fonts I have
been using all the time Garamond and marker felt from the dropdown. In fact
the highlighted text is in Helvetica which does not show as missing????
First, please delete your personal info when replying by email.
Next, is the pink text supposed to be in Helvetica? I'm guessing that perhaps the Helvetica has been substituted as the default font, and it really should be the Garamond or Marker Felt...