# Beamer Metropolis theme overfull vbox error on title page

I'm trying to make slides for a course I'm teaching this coming semester using beamer and I have a nagging issue with an overfull vbox that I can't diagnose when using the metropolis theme. Here is the minimal example. Note, I'm using pdflatex (for microtype features):

% !TEX program = pdflatex
% !TEX spellcheck = en_US

\documentclass[aspectratio=169]{beamer}

% Font Settings

\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[autostyle,english=american]{csquotes}
\usepackage[sfdefault,scaled=0.85,lf]{FiraSans}
\usepackage[scaled=0.85]{FiraMono}
\usepackage{newtxsf}
\usepackage[protrusion,expansion,kerning,spacing,final]{microtype}
\microtypecontext{spacing=nonfrench}

% PDF Bookmarks

\usepackage{bookmark}

% Beamer Setup

\usetheme{metropolis}
\usecolortheme{owl}

% AMS Math Packages

\usepackage{amsmath}

\title{A minimal example}
\date{\today}
\author{Matthias Vogelgesang}
\institute{Centre for Modern Beamer Themes}
\begin{document}
\maketitle %<-- here is where i get an "Overfull \vbox (15.63992pt too high)"
\section{First Section}
\begin{frame}{First Frame}
Hello, world!
\end{frame}
\end{document}


I basically pulled this example from the package documentation but included my own preamble. To my knowledge I have the current version of all packages except for babel (which is at 3.18 on my system).

• I don't get any error messages … – current_user Aug 3 '18 at 1:44
• I also do not get an error when I compile with pdflatex, but I do get one with xelatex. However, as you are saying you use pdflatex I cannot reproduce the issue either. – user121799 Aug 3 '18 at 2:05
• An overfull vbox is not an error, it is a warning and as such you can (mostly) ignore it. – TeXnician Aug 3 '18 at 6:16

The theme is not very careful regarding spurious spaces. If one removes the one from the titlepage definition the warning disappears (but there are more ...):

\documentclass[aspectratio=169]{beamer}

% Font Settings

\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[autostyle,english=american]{csquotes}
\usepackage[sfdefault,scaled=0.85,lf]{FiraSans}
\usepackage[scaled=0.85]{FiraMono}
\usepackage{newtxsf}
\usepackage[protrusion,expansion,kerning,spacing,final]{microtype}
\microtypecontext{spacing=nonfrench}

% PDF Bookmarks

\usepackage{bookmark}

% Beamer Setup

\usetheme{metropolis}
\usecolortheme{owl}

% AMS Math Packages

\usepackage{amsmath}

\title{A minimal example}
\date{\today}
\author{Matthias Vogelgesang}
\institute{Centre for Modern Beamer Themes}
\def\titlepage{%
\usebeamertemplate{title page}%<---
}
\begin{document}
\maketitle %<-- here is where i get an "Overfull \vbox (15.63992pt too high)"

\section{First Section}
\begin{frame}{First Frame}
Hello, world!
\end{frame}
\end{document}