I run into a problem with T5-encoding and a font family which doesn't support this encoding. I did sent a question on tex.SX: http://tex.stackexchange.com/questions/237188/corrupted-nfss-tables In my opinion the fd-file for the "fallback" font is loaded to late in \[log in to unmask] I found a workaround but I'm in no way sure that it hasn't some unwanted side-effects. \documentclass{book} \usepackage[T5,T1]{fontenc} \makeatletter \def\wrong@fontshape{% \csname D@\f@encoding\endcsname % install defaults if in math \edef\reserved@a{\csname\curr@fontshape\endcsname}% \ifx\last@fontshape\reserved@a \errmessage{Corrupted NFSS tables}% \error@fontshape \else \let\f@shape\default@shape \expandafter\ifx\csname\curr@fontshape\endcsname\relax \let\f@series\default@series \expandafter \ifx\csname\curr@fontshape\endcsname\relax \let\f@family\default@family \fi \fi \fi \@font@warning{Font shape `\expandafter\string\reserved@a' \expandafter\@gobble\string\@undefined\MessageBreak using `\curr@fontshape' instead\@wrong@font@char}% \begingroup\try@load@fontshape\endgroup %<--------------new \global\let\last@fontshape\reserved@a \gdef\@defaultsubs{% \@font@warning{Some font shapes were not available, defaults substituted.\@gobbletwo}}% \global\expandafter\expandafter\expandafter\let \expandafter\reserved@a \csname\curr@fontshape\endcsname \xdef\font@name{% \csname\curr@fontshape/\f@size\endcsname}% \pickup@font} \makeatother \renewcommand\rmdefault{fve}%no T5fve.fd \fontencoding{T1}\fontfamily{\familydefault}\selectfont \fontencoding{T5}\selectfont \selectfont %error \begin{document} blub \end{document} -- Ulrike Fischer http://www.troubleshooting-tex.de/