FatalDocument Structure
Preamble-Only Command Used in Body
! LaTeX Error: Can only be used in preamble.
What this error means
A command that can only appear in the preamble (before \begin{document}) was used inside the document body. Common offenders are \documentclass, \usepackage, and \pagestyle.
Common causes
- \usepackage or \documentclass placed after \begin{document}
- \pagestyle{} used in the body instead of the preamble
- Preamble commands accidentally placed at the end of the file
How to fix it
Move the offending command to the preamble, before \begin{document}. If you need to change page style mid-document, use \thispagestyle{} instead of \pagestyle{}.
Code examples
Causes the error
\documentclass{article}
\begin{document}
\usepackage{graphicx} % Too late! Must be in preamble
\includegraphics{image.png}
\end{document}Fixed
\documentclass{article}
\usepackage{graphicx} % Correct: in preamble
\begin{document}
\includegraphics{image.png}
\end{document}Related errors
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