Hello, This is caused by fontspec, I'd say, due to somewhat recent changes in the expl3 supporting package: \c_keys_code_root_tl was renamed \c__keys_code_root_tl at some point, to reflect its internal nature, and fontspec should not be using it. I don't know if this was fixed in more recent versions of fontspec (it seems to be). I've added the maintainer in Cc.
In the mean time, a temporary (ugly) workaround is to add \expandafter\providecommand \csname c_keys_code_root_tl\endcsname * {\csname c__keys_code_root_tl\endcsname} early in your document. Best regards, Bruno On 5/30/13, Gurebu Bokofu <gurebu_bok...@hotmail.com> wrote: > Hello everybody! > I need to use xeCJK and fontspec packages,however, when I try to load either > of xeCJK or fontspec ,it reads > ("C:\Program Files (x86)\MiKTeX2.9\tex\latex\fontspec\fontspec.cfg"! > Undefined control sequence.<argument> \c_keys_code_root_tl > fontspec/Ligatures/Historicall.8 > ...tureoption{Ligatures}{Historic}{Historical} > Also, same message will be if to load xeCJK only: > \documentclass{article}\usepackage{xeCJK} > \begin{document}This is the XeLaTeX test.\end{document} > By other words, XeLaTeX do not understand the package, isn't it? > Regards,Gleb. -------------------------------------------------- Subscriptions, Archive, and List information, etc.: http://tug.org/mailman/listinfo/xetex