# The fontspec package requires either XeTeX or LuaTeX to function [closed]

I am not an expert in LaTeX, but I was writing a paper, everything was going fine, until it suddenly crashed giving me the error:

The fontspec package requires either XeTeX or LuaTeX to function.

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That means that you have to use `xelatex <document>` or `lualatex <document>` instead of `pdflatex <document>` to compile your document if you want to use the `fontspec` package. For some background, try tex.stackexchange.com/q/36/86 – Andrew Stacey Oct 4 '12 at 8:49
Welcome to TeX.sx! Usually, we don't put a greeting or a "thank you" in our posts. While this might seem strange at first, it is not a sign of lack of politeness, but rather part of our trying to keep everything very concise. Upvoting is the preferred way here to say "thank you" to users who helped you. – Stephen Oct 4 '12 at 9:16
This can't have happened suddenly. Either you changed how you compile your document (now using `pdflatex` instead of `xelatex` for example) or you added `fontspec` explicitly or a package that loads `fontspec` implicitly. – cgnieder Oct 4 '12 at 11:07
As the error message said, LuaLaTeX or XeLaTeX should be used. Probably it wasn't the case. Since no further information was given, the question will now be closed as too localized. – Stefan Kottwitz Oct 18 '12 at 12:20

## closed as too localized by lockstep, Stefan Kottwitz♦Oct 18 '12 at 12:20

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