I am using subfigure to arrange 3by2 subfigures with captions each of them. Normally, the captions should look like this: (a) , (b). But instead they look like this: ((a)) , ((b)).
MWE:
\documentclass[a4paper, 10pt, openany]{memoir}
\usepackage[demo]{graphicx}
\usepackage{caption}
\usepackage{subcaption}
% Enable subfigures
\newsubfloat{figure}
% Section numbering depth
\maxtocdepth{subsection}
\maxsecnumdepth{subsection}
% Make floats name bold
\captionnamefont{\bfseries}
\captionstyle{\OnehalfSpacing}
\begin{document}
\begin{figure}[t!] % "[t!]" placement specifier just for this example
\begin{subfigure}{0.5\textwidth}
\includegraphics[trim=15 3 32 20,clip,width=\linewidth]{pss_off_powr4072.eps}
\subcaption{???? Power} \label{fig:pss_off_p4072}
\end{subfigure}\hspace*{\fill}
\begin{subfigure}{0.5\textwidth}
\includegraphics[trim=15 3 32 20,clip,width=\linewidth]{pss_off_powr40414061.eps}
\subcaption{????? Line Flow} \label{fig:pss_off_pflow}
\end{subfigure}
\medskip
\begin{subfigure}{0.5\textwidth}
\includegraphics[trim=15 3 32 20,clip,width=\linewidth]{stab2_powr4072.eps}
\subcaption{?????? Power} \label{fig:stab2_p4072}
\end{subfigure}\hspace*{\fill}
\begin{subfigure}{0.5\textwidth}
\includegraphics[trim=15 3 32 20,clip,width=\linewidth]{stab2_powr40414061.eps}
\subcaption{???? Line Flow 4041-4061} \label{fig:stab2_pflow}
\end{subfigure}
\medskip
\begin{subfigure}{0.5\textwidth}
\includegraphics[trim=15 3 32 20,clip,width=\linewidth]{stab1_2_powr4072.eps}
\subcaption{???????? Power} \label{fig:stab1_2_p4072}
\end{subfigure}\hspace*{\fill}
\begin{subfigure}{0.5\textwidth}
\includegraphics[trim=15 3 32 20,clip,width=\linewidth]{stab1_2_powr40414061.eps}
\subcaption{???????? Line Flow} \label{fig:stab1_2_pflow}
\end{subfigure}
\caption{Comparison} \label{fig:pss_comparison}
\end{figure}
\end{document}

\documentclassand end with\end{document}and not contain any unnecessary information; only stuff pertinent to replicate the current problem. That is, no need formathtools, orenumitem, or<whatever>, as that doesn't play a part with sub-figures. – Werner Jan 22 '16 at 21:15Class memoir Warning: You are using the caption package with the memoir class.memoir has its own mechanisms for caption formatting and if possible it's best to use those. (I don't really know memoir that well to give details) – David Carlisle Jan 22 '16 at 21:46\labels. Finally, showing only two subfigures would suffice since it would highlight the problem equally well than displaying six subfigures. – Werner Jan 22 '16 at 22:01