Latex: Error: ! LaTeX Error: Too many unprocessed floats.

When using too much floating figures or tables, latex fails to locate those elements, you may counter the error:

! LaTeX Error: Too many unprocessed floats.

. One of solutions is to use the package 'float' and add [H] in your figure environment. Example:

\usepackage{float} %before text body

\begin{figure}[H]
\centering
\includegraphics[width=0.8\textwidth]{fig_tauid/plot_compare_tauprop_allvar_TTauAndTauIDTree_20080814_Tau_dalpha.eps}
\caption{Comparison between different samples used in tau ID study.}
\end{figure}