LaTeX error · Packages, files and fonts

I can't find file `chapter1'

The error in the log

This is how the message appears in the .log file (and in the compile output). The line starting with l. is the line number where TeX noticed the problem; the real mistake is there or just before it.

! I can't find file `chapter1'.
l.3 \input chapter1
                   
*** (job aborted, file error in nonstop mode)

Why it happens

• The file is missing or in another folder: paths in \input are relative to the main file, not to the file containing the command.
• The name differs in case or spelling (Linux servers and online editors are case-sensitive: Chapter1.tex is not chapter1.tex).
• A file name with spaces or special characters, which TeX reads only up to the space.
• The compiler was started on a file name that does not exist, for example the wrong main file in the project settings.

How to fix it

Make the file exist where LaTeX looks for it, and refer to it with braces and the path from the main file: \input{chapters/chapter1}. Rename files to avoid spaces.

In the example below filecontents writes chapter1.tex so the snippet is self-contained; in a real project it is a separate file next to the main one.

Broken: reproduces the error

\documentclass{article}
\begin{document}
\input chapter1
\end{document}

Fixed: compiles cleanly

\begin{filecontents*}[overwrite]{chapter1.tex}
This is the first chapter.
\end{filecontents*}
\documentclass{article}
\begin{document}
\input{chapter1}
\end{document}

Related errors

• File not found – A package or class named in \usepackage or \documentclass is misspelled or not installed.
• Emergency stop – The run was aborted; the reason is in the line after it or in the error just above.
• Missing \begin{document} – Something printable sits in the preamble, before \begin{document}.
• All LaTeX errors and warnings – The full list, grouped by cause

Frequently Asked Questions

What is the difference between this and "File not found"?

"I can't find file" is the low-level TeX message, printed when the primitive \input or the compiler cannot open a file. "LaTeX Error: File `x' not found" is LaTeX's own message for \usepackage, \documentclass and braced \input{...}.

Should I use \input or \include?

\input{file} inserts the file exactly where it is, anywhere in the document. \include{file} starts a new page and works with \includeonly to compile selected chapters. Both need the file to exist under that path.

Why does it work on my computer but not online?

Online editors usually run on Linux, where file names are case-sensitive, and only see the files you uploaded. Check the capitalisation and that every input file is part of the project.