Hello, When an \errmessage is issued with \errhelp set to be non-empty, LuaTeX shows the message "Type <return> to proceed [etc]" immediately after the \errhelp. Other engines suppress this message in the presence of \errhelp. I don't know if the difference is voluntary. In any case, it would seem better to add a newline between the \errhelp text and the built-in "Type..." text. On a Unix machine with TeXlive installed, echo "H" | luatex '\errhelp{ABC}\errmessage{BOOM}' prints the following to the terminal (a similar result is obtained if the TeX code is put in a file) This is LuaTeX, Version beta-0.70.2-2012062812 (TeX Live 2012) restricted \write18 enabled. ! foo. <*> \errhelp{ABC}\errmessage{foo} ? ABCType <return> to proceed, S to scroll future error messages, R to run without stopping, Q to run quietly, I to insert something, 1 or ... or 9 to ignore the next 1 to 9 tokens of input, H for help, X to quit. ? ! Emergency stop. <*> \errhelp{ABC}\errmessage{foo} ! ==> Fatal error occurred, no output PDF file produced! Transcript written on texput.log. I would like to know whether this lack of newline is a bug or not, to know if I should add LuaTeX-specific code to the l3msg LaTeX3 package. Regards, Bruno