FormaTeX
FatalCommands & Packages

Runaway Argument (Missing Closing Brace)

Runaway argument?

What this error means

LaTeX started reading a mandatory argument (inside {}) but reached a paragraph break or end-of-file before finding the closing }. This typically means a brace was opened but never closed.

Common causes

  • A { was opened to start a command argument but no matching } was written
  • A blank line inside a command argument (paragraph breaks are not allowed inside arguments)
  • Copy-pasting code that dropped the closing brace

How to fix it

Find the unclosed { and add the matching }. Check the line indicated in the error. Blank lines inside command arguments are not allowed — if you need to break, end the command first.

Code examples

Causes the error
\documentclass{article}
\begin{document}

\textbf{This text is bold

and continues on a new paragraph}

\end{document}
Fixed
\documentclass{article}
\begin{document}

\textbf{This text is bold.}

And continues on a new paragraph.

\end{document}

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