Since KDE 5, notification sounds are really annoying. Even on a high performance pc, appearing notification, cautions, warning or any related MessageBox is so laggy and it's because of the way KDE/KF handles playing notification sounds. Now, I want to disable notification sounds hopping that MessageBoxes apprear faster.

PS: I have googled a lot and read many similar topis including the one which described how to disable notification sounds throught SystemSettings/Notifications on by one. But I want to disable all of them at once. I actually want to disable sound playing feature.

see System Settings>Notifications>Event Notifications and Actions
You'll note that there are 24 Event sources
There is a single click option to disable all sounds for an event
(so you only need do this 24 times)
Trust that helps...

So how to disable sound for volume up/down?

jerrysl wrote:So how to disable sound for volume up/down?

Audio volume setting -> General -> Behavior Volume Feedback

I tried disabling notification sounds for everything in system-> Notifications but it didn't work

here is the only method I found that actually works:

mv /usr/share/sounds $HOME/usr_share_sounds

or you could just

rm -R /usr/share/sounds

then reboot the system. No more notification sounds.