Is this the desired output:
\documentclass[]{beamer}
\begin{document}
\begin{frame}{Motivation}
\begin{minipage}{0.6\textwidth}
\vbox to \textheight{
\vfill
\centering
\includegraphics[width=1\textwidth]{example-image}
\vfill
}
\end{minipage}\hfill
\begin{minipage}{0.4\textwidth}
\vbox to \textheight{
\begin{itemize}
\item 1
\item 2
\item 3
\item 4
\item 5
\item 6
\end{itemize}
\vfill
}
\end{minipage}
\end{frame}
\end{document}

You could achieve the more or less same with the optional arguments of minipage:
\documentclass[t]{beamer}
\begin{document}
\begin{frame}{Motivation}
\begin{minipage}[c][\textheight][c]{0.6\textwidth}
\centering
\includegraphics[width=1\textwidth]{example-image}
\end{minipage}\hfill
\begin{minipage}[c][\textheight][t]{0.4\textwidth}
\begin{itemize}
\item 1
\item 2
\item 3
\item 4
\item 5
\item 6
\end{itemize}
\end{minipage}
\end{frame}
\end{document}

To get better results of vertical placement, one could use the code provided in this answer to calculate the \contentheight which is the height of the frame without the title and stuff.
With this we could further automate the process (note that 0.95\contentheight gives better vertical centering of the image):
\documentclass[t]{beamer}
\newif\ifsidebartheme
\sidebarthemefalse
\newdimen\contentheight
\newdimen\contentwidth
\newdimen\contentleft
\newdimen\contentbottom
\makeatletter
\newcommand*{\calculatespace}{%
\contentheight=\paperheight%
\ifx\beamer@frametitle\@empty%
\setbox\@tempboxa=\box\voidb@x%
\else%
\setbox\@tempboxa=\vbox{%
\vbox{}%
{\parskip0pt\usebeamertemplate***{frametitle}}%
}%
\ifsidebartheme%
\advance\contentheight by-1em%
\fi%
\fi%
\advance\contentheight by-\ht\@tempboxa%
\advance\contentheight by-\dp\@tempboxa%
\advance\contentheight by-\beamer@frametopskip%
\ifbeamer@plainframe%
\contentbottom=0pt%
\else%
\advance\contentheight by-\headheight%
\advance\contentheight by\headdp%
\advance\contentheight by-\footheight%
\advance\contentheight by4pt%
\contentbottom=\footheight%
\advance\contentbottom by-4pt%
\fi%
\contentwidth=\paperwidth%
\ifbeamer@plainframe%
\contentleft=0pt%
\else%
\advance\contentwidth by-\beamer@rightsidebar%
\advance\contentwidth by-\beamer@leftsidebar\relax%
\contentleft=\beamer@leftsidebar%
\fi%
}
\makeatother
\begin{document}
\begin{frame}
\calculatespace%
\begin{minipage}[c][0.95\contentheight][c]{0.6\textwidth}%
\centering%
\includegraphics[width=1\textwidth]{example-image}%
\end{minipage}\hfill%
\begin{minipage}[c][0.95\contentheight][t]{0.4\textwidth}%
\begin{itemize}%
\item 1%
\item 2%
\item 3%
\item 4%
\item 5%
\item 6%
\end{itemize}%
\end{minipage}%
\end{frame}
\end{document}
\documentclass{...}, the required\usepackage's,\begin{document}, and\end{document}. That may seem tedious to you, but think of the extra work it represents for TeX.SX users willing to give you a hand. Help them help you: remove that one hurdle between you and a solution to your problem. – dexteritas Jul 24 '17 at 13:14