# Why can't I use my font with unicode-math?

\documentclass{article}
\usepackage{unicode-math}

\setmathfont{Latin Modern Sans}

\usepackage{mwe}
\blindmathtrue

\begin{document}
\Blinddocument
\end{document}


The above fails with the error

ERROR: Internal error: bad native font flag in map_char_to_glyph'

--- TeX said ---
--- HELP ---
No help available


What is causing this error and how can I pick fonts to avoid this in the future?

• Latin Modern Sans has no math table. You have to use a font which has it, such as Latin Modern Math. If you want to use a font without a math table in mathmode with xelatex you have to use the mathspec package. – Henri Menke Feb 7 '15 at 15:23
• See also my question here: tex.stackexchange.com/questions/118244/… – Henri Menke Feb 7 '15 at 15:23
• not having a math table is perhaps a sign that it's not intended for math, as with classic tex math fonts though, once you have set up the main math font, you can if required set up text fonts for use as math alphabets – David Carlisle Feb 7 '15 at 15:26
• For explanation, see my answer here: tex.stackexchange.com/a/166185. For information on fonts which will work, see my answer here: tex.stackexchange.com/a/219414. – cfr Feb 7 '15 at 15:31

You have two options to overcome this issue.

# 1. Use an OpenType Math Font

For unicode-math to work you have to use an OpenType font which provides the math table, such as Latin Modern Math. This unfortunately defeats the implicit purpose of your MWE to use a sans serif font for maths.

\documentclass{article}
\pagestyle{empty}
\usepackage{unicode-math}
\setmathfont{Latin Modern Math}
\begin{document}
Lorem ipsum
$\sum_{k=0}^\infty a_0q^k = \lim_{n\to\infty}\sum_{k=0}^n a_0q^k = \lim_{n\to\infty} a_0\frac{1-q^{n+1}}{1-q} = \frac{a_0}{1-q}$
dolor sit amet
\end{document}


# 2. Use the mathspec Package

The mathspec allows to use any OpenType font for mathmode (at the cost of bad spacing).

\documentclass{article}
\usepackage{mathspec}
\setmathfont(Latin,Digits,Greek){Latin Modern Sans}
\setmathrm{Latin Modern Sans}
\begin{document}
Lorem ipsum
$\sum_{k=0}^\infty a_0q^k = \lim_{n\to\infty}\sum_{k=0}^n a_0q^k = \lim_{n\to\infty} a_0\frac{1-q^{n+1}}{1-q} = \frac{a_0}{1-q}$
dolor sit amet
\end{document}
`