Dear Lars Madsen, > I'm not looking for a solution to the problem just an explanation as to > how exactly mktexpk is called from pdflatex on Windows. I don't know texstudio and your problem, but mktexpk is called like retvalue = _spawnvp(_P_NOWAIT, $SELFAUTOLOC\mktexpk.exe, (const char * const *) args); Best, Akira