Dear list members, The below MWE runs fine and generates a usable PDF. If I uncomment the second question block and run the MWE on a OS X system it generates an unusable PDF and a nearly empty log file: open source > level 1, order 1, name 'cont-yes.mkiv' system > system > ConTeXt ver: 2019.10.28 18:57 MKIV beta fmt: 2019.11.7 int: english/english system > system > 'cont-new.mkiv' loaded open source > level 2, order 2, name '/Users/JW/context/tex/texmf-context/tex/context/base/mkiv/cont-new.mkiv' system > beware: some patches loaded from cont-new.mkiv close source > level 2, order 2, name '/Users/JW/context/tex/texmf-context/tex/context/base/mkiv/cont-new.mkiv' system > files > jobname 'co-intro', input './co-intro', result 'co-intro' fonts > latin modern fonts are not preloaded languages > language 'en' is active system > synctex functionality is enabled, expect 5-10 pct runtime overhead! open source > level 2, order 3, name './co-intro.tex' fonts > preloading latin modern fonts (second stage) fonts > 'fallback modern-designsize rm 12pt' is loaded open source > level 3, order 4, name 'knuth.tex' close source > level 3, order 4, name 'knuth.tex' I cannot reproduce the problem on a Windows system. Can somebody on an OS X system check and confirm the issue? Thanks, Jan Willem Flamma ==== \defineblock[question] \defineblock[answer] \hideblocks[question] \hideblocks[answer] \defineenumeration[question] \defineenumeration[answer] \starttext \input knuth \beginquestion \startquestion Question text \startitemize[a] \item Answer A \item Answer B \item Answer C \stopitemize \stopquestion \endquestion \beginanswer \startanswer A \stopanswer \endanswer %\beginquestion %\startquestion %Questions text %\startitemize[a] %\item Answer A %\item Answer B %\item Answer C %\stopitemize %\stopquestion %\endquestion %\beginanswer %\startanswer %A %\stopanswer %\endanswer \useblocks[question] \stoptext