Dear Thomas, Thank you for your reply. XeTeX+ ConTeXt is working after adding a command as you said. (customize-variaable) But Lua + ConTeXt is not working. If I do "mtxrun --script context ...", then it complains. %%%%%%% Running `Other' on `test-lua' with ``mtxrun --script context %t'' MtxRun | unknown script: context %%%%%%%%%%%%%%%%% If I changed the command "texmfstart texexec --lua %t", then I got the following. Running `LuaConTeXt' on `test-lua' with ``texmfstart texexec --lua test-lua.tex'' TeXExec | processing document 'test-lua.tex' TeXExec | no ctx file found TeXExec | tex processing method: context TeXExec | TeX run 1 TeXExec | writing option file test-lua.top TeXExec | using randomseed 828 TeXExec | tex engine: luatex TeXExec | tex format: cont-en LuaTools | using format name /Users/dalyoung/luatex-cache/context/ 5759d5068ca15ba6658b2e6454390744/formats/cont-en.fmt LuaTools | no luc/lua with name /Users/dalyoung/luatex-cache/context/ 5759d5068ca15ba6658b2e6454390744/formats/cont-en LuaTools | LuaTools | runtime: 0.023 seconds TeXUtil | parsing file test-lua.tui TeXUtil | shortcuts : 169 TeXUtil | expansions: 308 TeXUtil | reductions: 0 TeXUtil | divisions : 0 TeXUtil | loaded files: 1 TeXUtil | temporary files: 0 TeXUtil | commands: 21 TeXUtil | programs: 0 TeXUtil | tuo file saved TeXExec | runtime: 0.891602 LuaConTeXt finished at Sat May 17 16:14:24 However, the same command worked well in a terminal. Maybe the system setup of yours is different from mine. Usually I run "source .luatex" first before running luatex. So my guess is that emacs couldn't know the luatex path even though it is known in another program "terminal". Am I correct? If so, how to apply environment .luatex to global condition? Otherwise, what are wrong in my setup? Thank you. Best regards, Dalyoung Jeong