Recently, I'm not exactly sure when, AucTeX has started giving me trouble by reporting "Problems after {n} pages." for any document generating n pages.
For example, the file
\documentclass{article}
\begin{document}
foobar
\end{document}
when compiled with C-c C-c in AucTeX compiles successfully, but gives the message "LaTeX: problems after 1 page." There are not errors at all. The log file looks clean to me. It does not say what are the "problems" in question.
One consequence is that the C-c C-c cycle gets stuck at LaTeX, because of aforesaid "problems".
I've used AucTex on Aquamacs on a Mac for many many years. This has cropped up recently, but I don't know why. Can anyone help?
This question was asked and answered on AUCTeX mailing list, I'm reposting the answer here as well.
This is a known issue occurring with outdated versions of AUCTeX used in combination with recent versions of the TeX system, for example that shipped with TeX Live 2017. The bug has been already fixed upstream, you only have to update AUCTeX (to version 11.90.2 or higher). The recommended way to install the package is by using GNU ELPA, see https://elpa.gnu.org/packages/auctex.html