With version :ConTeXt ver: 2016.02.17 11:11 MKIV beta the following code worked: \define[2]\Illustration{% \startplacefigure [title=#2,reference=fig:#1] \externalfigure[#1][height=.25\textheight] \stopplacefigure} \starttext \Illustration{cow}{A Frisian cow} \stoptext With ConTeXt ver: 2016.03.03 23:31 MKIV beta I get a fatal error: ...test.tex: ! Extra }, or forgotten \endgroup \strc_counters_register_component_list ...focus }}titledata{label{\detokeniz... \strc_counters_register_component ...}{#3}{#4}{#9}\else \ifx \currentstructu... \strc_floats_place_packaged_boxes_indeed ... ][#1]\globallet \previousfloatn... \strc_floats_finish_placement ...e_packaged_boxes\dostoptagged \global \d_p... l.30 \Illustration{cow}{A Frisian cow} Kind regards Willi