# Fatal error in latex

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.

• your question is just about the editor you are using, but you have not said which editor that is. On the command line, calling latex directly switching from pdflatex to xelatex simply means typing xelatex file instead of pdflatex file. – David Carlisle Jan 25 '18 at 22:07

## 1 Answer

You can either go to the Tools -> Commands menu and choose xelatex, like this:

Or, change the default compiler, go to the Options -> Configure TeXstudio, choose the Build icon and change the default in the editing window:

• It wouldn't still work. The error provided is as stated below. Undefined control sequence. \begin{document} Missing number, treated as zero. \begin{document} Font \fb=''[cmr10]'' not loadable: metric data not found or bad. XLTXTRA IS TO BE USED ONLY UNDER XETEX. LOAD FONTSPEC DIRECTLY, INSTEAD. – user3407190 Jan 25 '18 at 21:41
• Did you click on OK after you've changed the default compiler? – Bernard Jan 25 '18 at 21:47
• Yes I did that. – user3407190 Jan 25 '18 at 21:53
• Which distribution do you have, on which system? – Bernard Jan 25 '18 at 21:55