"fatal error occurred, no output pdf produced"

Question

I am trying to run my LaTeX file but it keeps coming up with the message above. All I tried to do was insert an equation and it all of a sudden happened. I haven't got the pdf open and my document starts like this:

\documentclass[12pt]{report}
\usepackage{a4,amsmath,amssymb,url}
\usepackage[active]{srcltx}
\usepackage{graphicx}
\usepackage{natbib}
\usepackage{mathrsfs}
\graphicspath{ {C:/Users/Edd/Documents/uni/uni maths/Year 3/investigatoin/} }
\usepackage[utf8]{inputenc}
\renewcommand{\thesection}{\arabic{section}}
\setlength{\parskip}{0.5cm}

\title{Computing and Computability}
\author{Edward J. Russell}
\begin{document}
\maketitle
\tableofcontents

and ends like this:

\bibliography{bibfile}
\bibliographystyle{plain}
\end{document}

Answer 1

"I can't write on the file 'investigation.pdf'. 
Please type another file name for output" 

for line 15 which is the line \maketitle

that is not really a TeX error, the title just happens to be the start of the typeset text so the point at which Tex starts producing the output pdf file.

It is blocked from creating that file, this could be one of several reasons none directly connected to the specifics of the TeX code. The system could be banning writing to that file or that folder due to use access settings or (most commonly) adobe acrobat or some other application could be holding the file open and blocking write access or various other system or network effects.

David