Beamer warning `pdfauthor' has already been used

Question

I'm using the minimal example presented in this old Answer, even though, still I encounter this warning:

Package hyperref Warning: Option 'pdfauthor' has already been used, setting the option has no effect on input line 12.

Can you please suggest to me a neat solution to remediate this annoying warning? thanks in advance.

Answer 1

You move all the \author, \title etc into the preamble. Beamer will automatically use this information at the start of the document to create the meta data for the pdf. If you only use them after the start of the document, that's too late for beamer.

\documentclass[presentation]{beamer}
%\let\Tiny\tiny
%\usepackage{hyperref}
\usetheme{Berkeley}
\author[A,B,C]{A\inst{1}  \and B\inst{2}  \and C\inst{2}}
\renewcommand{\thefootnote}{$\aleph$}
\title[Cross]{\large Experimental Studies %
\thanks{\scriptsize Project supported by foundation:  Supported by the National Nature Science Foundation}}
% Old style
%\author[A,B,C]{A$^1$,
%B$^1$
%and C$^2$}
\institute[Fluid Mechanics]{$^1$Department of Mechanics & Engineering Science\
$^2$College of Science}
\date[The second presentation, 2013]{The second presentation, 2013}
%\logo{\includegraphics[height=16pt]{picture/Fudanlog.PNG}}
\date[\initclock\tdtime]{\today}
\begin{document}
\begin{frame}
\titlepage
\end{frame}
\section{A section}
\subsection{A subsection}
\begin{frame}
  \frametitle{Frame title1}
  \framesubtitle{frame subtitle1}
  Some text s
\end{frame}
\end{document}