Exactly as the description says, The sound notifications are not working in Linux Mint 18.2 Cinnamon edition. In fact, I have never heard a sound out of kstars on my Linux Mint installs. I know sound works on the system because I have startup sounds. I have no doubt I am missing something trivial like an underlying sound package that is required by the system or maybe an environment variable. Does anyone have any ideas on this?

That is fixed in the next KStars release due tomorrow.

Awesome. Once again I report something that's already being fixed. I am batting 1000.

The update I installed today did not seem to fix the sound notifications. I see that several sounds were set, but when you click the play button in the Configure Notifications selections it does not make any sound. Again, I know sound works on my Linux Mint system because I hear sounds from everything else. Is there anything you want me to try or check?

Try this:

Is required also this: Phonon GStreamer 1.0.x backend

sudo apt-get install phonon-backend-gstreamer-common

That is already installed on my system but the sounds are still not working in kstars. Any other ideas on this one?

I didn't have the phonon4qt5-backend-vlc package installed. I installed that. At first it did not work, but it did work after I rebooted the machine. I think we are good to go on this one now. Is there a way to make that a required package so this doesn't bite someone else?

Yeah I added it now as a dependency.