In this MWE ```tex \documentclass{scrartcl} \usepackage[spanish, activeacute]{babel} \usepackage{unicode-math} \usepackage{hyperref} \begin{document} \section{A section} \begin{equation} j =\sqrt{-1} \end{equation} \end{document} ``` there is a fatal error. However, if I comment `activeacute` or `\usepackage{hyperref}` or `\usepackage{unicode-math]` or I change the kind of document to article, for example, the error disappears. Any help? Thanks

or

I did not test thoroughly whether all the features work, but it seems like loading `babel` after `unicode-math` fixes the issue at hand. ```tex \documentclass{scrartcl} \usepackage{unicode-math} \usepackage[spanish, activeacute]{babel} \usepackage{hyperref} \begin{document} \section{A section} 'a \begin{equation} j =\sqrt{-1} \end{equation} \end{document} ```