Solution to MPD failure to start

Have you correctly installed and configured your MPD in a Linux distro but whenever you start MPD, it fails?
Here's a possible cause and a solution:
Changing the group that MPD runs as may result in errors like
"output: Failed to open"My ALSA Device"" "[alsa]: Failed to open ALSA device"default": No such file or directory" "player_thread: problems opening audio device while playing "Song Name.mp3""

This is because by default MPD runs as member of audio group and the sound devices under/dev/snd/are owned by this group.
The solution is to add user mpd to groupaudio:
# gpasswd -a mpd audio