Can you replicate this, Richard, eliminating LaTeX and its packages from the equation ? At the moment, your report seems to finger LaTeX or one of its packages rather than XeTeX /qua/ XeTeX : >> Missing = inserted for \ifnum >> <to be read again> >> \l_fontspec_font >> 1.39 \newfontfamily{\H}[Scale=0.9]{Lucida Grande} Philip Taylor