As my computer died I had to set up a clean one. I installed MacTeX 2013 and tried to compile a ConTeXt project, but this failed: texexec --pdf --mode=editor --once ../products/prd_book.tex resolvers | caches | path '/Users/gerben/Library/texlive/2013/texmf-var' created/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require': /usr/local/texlive/2013/texmf-dist/scripts/context/ruby/base/switch.rb:501: invalid multibyte escape: /\xFF/ (SyntaxError) from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require' from /usr/local/texlive/2013/texmf-dist/scripts/context/ruby/texexec.rb:11:in `<main>' It seems a problem in a ruby file in MacTeX 2013. Can someone help me get this working? Thanks, G