I have tried mp3, m4a and flac and get the same error:
GStreamer could not create the element: autoaudiosink. Please make sure that you have installed all necessary GStreamer plugins (e.g. OGG and MP3)
I can play these files in VLC but VLC is a clunky music player.
Do I need to install every gstreamer program? I have fluendo, ffmpeg, good, bad ugly already installed.
I didn’t have k3b-codecs installed, not sure that was part of the issue.
What fixed it was a reboot. Linux is becoming more windows-like.
Maybe restarting your session was enough ?
I’m pretty convinced installing k3b-codecs shouldn’t fix a Clementine problem.
Clementine used the Gstreamer & Gstreamer Good plugins (until recently it was gstreamer-0 packages but it has recently moved to the gstreamer-1 packages).