When opening a QuarkXPress document, you may get a message indicating that fonts are missing (some with odd names like -23421), yet when you open Utilities->Usage the fonts are aren’t listed as in use. If this happens, switch to the document’s Master Page(s), then open Utilities->Usage again. The fonts should be listed here, and the reason they didn’t show earlier is because missing fonts in style sheets and Master Page(s) are reported when you open a document, whether or not these fonts are applied to text.