LaTeX Common Errors & Troubleshooting

Fix LaTeX errors quickly with our comprehensive troubleshooting guide. Solutions for the most common LaTeX compilation errors and warnings.

Don’t panic! LaTeX errors can look scary, but most are easy to fix once you understand them. This guide covers the most common errors with clear solutions.

Quick tip: LaTeX error messages show the line number where the error occurred. Look for l.123 in the error message to find line 123 in your document.

Understanding LaTeX Error Messages

LaTeX errors follow this pattern:

! LaTeX Error: [Error description]

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              
                                                  
l.123 \textbf{This is the problematic line

Key parts:

• ! indicates an error (not a warning)
• Error description tells you what went wrong
• l.123 shows the line number
• The line content helps locate the issue

Most Common Errors

1. Missing $ inserted

Error message:

! Missing $ inserted.
<inserted text> 
                $
l.42 The value of x_1 is important

Cause: Math symbols used outside math mode

Solutions:

wrong.tex

The value of x_1 is important       % Wrong
The equation x^2 + y^2 = r^2 holds  % Wrong

Common math symbols that need math mode: _, ^, \alpha, \sum, etc.

2. Undefined control sequence

Error message:

! Undefined control sequence.
l.15 \textcolor
      {red}{This text}

Cause: Using a command that doesn’t exist or missing package

Solutions:

solution1.tex

% Add required package
\usepackage{xcolor}  % For \textcolor
\usepackage{amsmath} % For \text
\usepackage{graphicx} % For \includegraphics

3. Missing \begin

Error message:

! LaTeX Error: Missing \begin{document}.

Cause: Content before \begin{document} or missing the command entirely

Solution:

wrong.tex

\documentclass{article}
\title{My Document}

This is my text  % Wrong - content before \begin{document}

\begin{document}
\end{document}

4. File not found

Error message:

! LaTeX Error: File `mycustom.sty' not found.

Cause: Missing package, image, or bibliography file

Solutions:

1. Install missing package:

   tlmgr install packagename  # TeX Live
   # or use your TeX distribution's package manager
   

2. Check file paths:

   \includegraphics{images/photo.png}  % Make sure path is correct
   \bibliography{references}           % Check references.bib exists
   

3. Use correct file extensions:

   \usepackage{mycustom}     % Looks for mycustom.sty
   \input{chapter1}          % Looks for chapter1.tex
   

5. Missing } inserted

Error message:

! Missing } inserted.
<inserted text> 
                }
l.33 \textbf{Bold text

Cause: Unmatched braces

Solution:

wrong.tex

\textbf{Bold text         % Missing closing brace
\textit{Italic {nested}   % Missing closing brace
$x^{2+3$                  % Missing closing brace

Use a text editor with brace matching to catch these errors early.

6. Environment undefined

Error message:

! LaTeX Error: Environment equation* undefined.

Cause: Using an environment that doesn’t exist or missing package

Solution:

% For equation* environment
\usepackage{amsmath}

% Check spelling
\begin{ennumerate}  % Wrong
\begin{enumerate}   % Correct

7. Runaway argument

Error message:

Runaway argument?
{This is a very long...
! Paragraph ended before \textbf was complete.

Cause: Missing closing brace or bracket spanning paragraphs

Solution:

wrong.tex

\textbf{This is bold

This is a new paragraph}  % Error - can't span paragraphs

8. Overfull/Underfull hbox

Warning message:

Overfull \hbox (15.0pt too wide) in paragraph at lines 42--45

Cause: Text doesn’t fit properly in the line

Solutions:

1. Let LaTeX hyphenate:

   \usepackage[english]{babel}
   

2. Force hyphenation:

   super\-cali\-fragi\-listic
   

3. Rewrite the sentence

4. Allow stretchy spacing:

   \sloppy  % For whole document
   {\sloppy This problematic paragraph}  % For specific text
   

9. Table/Figure positioning problems

Issue: Tables or figures appear in wrong locations

Solutions:

positioning.tex

% Use positioning options
\begin{figure}[htbp]  % here, top, bottom, page
\centering
\includegraphics{image}
\caption{My figure}
\end{figure}

% Force position (not recommended)
\usepackage{float}
\begin{figure}[H]  % Exactly Here

10. Bibliography not showing

Issue: References not appearing

Solution sequence:

pdflatex document.tex
bibtex document       # or biber document
pdflatex document.tex
pdflatex document.tex

Error Categories

Math Mode Errors

Common math mode mistakes:

• Text in math: Use \text{...} from amsmath
• Wrong delimiter size: Use \left( and \right)
• Display math in wrong place: Can’t use $$ in some environments

math-fixes.tex

% Text in math mode
$x = 2 when y = 3$        % Wrong
$x = 2 \text{ when } y = 3$  % Correct

% Delimiter sizing
$(\frac{a}{b})$           % Small parentheses
$\left(\frac{a}{b}\right)$    % Auto-sized parentheses

% Display math
\begin{center}
$$x = y$$                 % Wrong in center environment
\end{center}

\begin{center}
$x = y$                   % Correct
\end{center}

Package Conflicts

Some packages don’t work well together:

% Common conflicts
\usepackage{subfigure}  % Old, conflicts with many
\usepackage{subfig}     % Use this instead

\usepackage{pdfpages}   % Load after graphicx
\usepackage{hyperref}   % Usually load last

Font Errors

% Font not found
\usepackage{times}      % Deprecated
\usepackage{mathptmx}   % Use this instead

% Font size errors
\fontsize{50}           % Wrong - missing unit
\fontsize{50pt}{60pt}\selectfont  % Correct

Debugging Strategies

1. Binary Search Method

Comment out half your document to isolate errors:

\begin{document}
First part...
%{
Second part...  % This part is now commented
%}
\end{document}

2. Minimal Working Example (MWE)

Create a minimal file that reproduces the error:

\documentclass{article}
\usepackage{[only needed packages]}
\begin{document}
[Minimal code that causes error]
\end{document}

3. Check the Log File

Look for:

• First error (fix this first)
• Line numbers
• Package warnings
• Overfull/underfull boxes

4. Common Quick Fixes

Clear auxiliary files

Delete .aux, .log, .toc files and recompile

Update packages

Keep your TeX distribution updated

Check encoding

Save files as UTF-8

Simplify first

Remove packages/commands until it works

Prevention Tips

Best practices to avoid errors:

1. Compile frequently (after every few lines when learning)
2. Use a good editor with syntax highlighting
3. Keep backups before major changes
4. Organize long documents into multiple files
5. Comment your code for complex parts
6. Use version control (Git)

Platform-Specific Issues

Windows

• Path issues: Use forward slashes / or double backslashes \\
• Font issues: Install fonts system-wide
• Encoding: Save as UTF-8, not ANSI

macOS

• Missing fonts: Install MacTeX fully
• Path issues: Don’t use spaces in filenames
• Preview issues: Use external PDF viewer

Linux

• Permission issues: Check file permissions
• Missing packages: Use distribution package manager
• Font issues: Update font cache

Getting Help

When asking for help online, include:

1. Minimal Working Example (MWE)
2. Complete error message
3. TeX distribution and version
4. What you’ve already tried

Help Resources

TeX StackExchange

Q&A community for TeX/LaTeX

LaTeX Community

Official LaTeX forum

Reddit r/LaTeX

Reddit community

CTAN

Package documentation

Quick Reference Card

Error	Quick Fix
Missing $	Wrap math in $...$
Undefined control sequence	Check spelling or add package
Missing }	Match all opening braces
File not found	Check path and filename
Overfull hbox	Add hyphenation or rewrite
Figure in wrong place	Use [htbp] positioning
Bibliography missing	Run BibTeX/Biber
Package unknown	Install with package manager

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Remember: Every LaTeX user encounters errors. They’re not a sign of failure but an opportunity to learn. The more errors you fix, the better you become at LaTeX!

Still stuck? Create a Minimal Working Example and ask for help in the community forums. Happy TeXing!