Package biblatex Error: Patching \addtocontents failed

Question

This is a bit urgent. I'm getting an error on my file (it complies on Overleaf but not on pdflatex), and I cannot figure out how to fix this. I've checked the documentation, and a lot of other stack overflow questions, but I can't figure this out.

Any suggestions?

Full error:

! Package biblatex Error: Patching \addtocontents failed.

See the biblatex package documentation for explanation.
Type  H <return>  for immediate help.

I don't actually use addtocontents anywhere, and I'm getting this error at \begin(document).

\documentclass{IOS-Book-Article}
\usepackage[utf8]{inputenc}

\makeatletter
\let\c@author\relax
\makeatother

\usepackage{graphicx}
\graphicspath{ {./images/} }

\usepackage{mathptmx}
\usepackage{stmaryrd}
\usepackage{array}
\usepackage{amsmath}
\usepackage{booktabs}
\usepackage{ragged2e}
\usepackage{bbold}

\usepackage{multirow}

\usepackage[compact]{titlesec}
\usepackage[dvipsnames]{xcolor}

\usepackage[backend=biber, style=vancouver, doi=false, isbn=false, url=false]{biblatex}

\addbibresource{references2.bib}
\AtBeginBibliography{\footnotesize}

...


\printbibliography
\end{document}

Answer 1

For strange reasons, the class does

\long\def\addtocontents#1#2{}

which is pretty useless because it doesn't even define \tableofcontents and alike commands so it's not a problem having \addtocontents do something.

You can avoid the error by replacing \addtocontents with its kernel meaning and do what the class wants later on (even if useless).

I'd avoid calling titlesec because the submission might be rejected for not being compliant.

\let\latexaddtocontents\addtocontents
\documentclass{IOS-Book-Article}
\let\addtocontents\latexaddtocontents

\usepackage[utf8]{inputenc}

\makeatletter
\let\c@author\relax
\AtBeginDocument{\let\addtocontents\@gobbletwo\setcounter{author}{0}}
\makeatother

\usepackage{graphicx}
\graphicspath{ {./images/} }

%\usepackage{mathptmx}
\usepackage{stmaryrd}
\usepackage{array}
\usepackage{amsmath}
\usepackage{booktabs}
\usepackage{ragged2e}
\usepackage{bbold}

\usepackage{multirow}

%\usepackage[compact]{titlesec}
\usepackage[dvipsnames]{xcolor}

\usepackage[backend=biber, style=vancouver, doi=false, isbn=false, url=false]{biblatex}

\addbibresource{references2.bib}
\AtBeginBibliography{\footnotesize}

\begin{document}

abc

\end{document}

I also added \setcounter{author}{0} because the class defines the counter for the purpose of \maketitle, but then it is needed by biblatex and in the body the value should start at zero as biblatex expects.