Hi there I am using texstudio version 2.12.6. I tried compiling a document (CV) but it keeps repeating the fatal error : "cannot-use-pdftex" The fontspec package requires either XeTeX or LuaTeX to function. You must change your typesetting engine to, e.g., "xelatex" or "lualatex" instead of plain "latex" or "pdflatex". For immediate help type H . I tried to configured the default compiler from pdflatex to xelatex but it will not just work. It keeps returning to pdflatex when I go back to check. Any help will be appreciated.