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