I have just installed Ubuntu 18.04 on my Asus UX490 and now I cannot change the volume but I can mute/unmute.
I can move the volume bar right/left but volume does not change. However, when I move it to left most side or just click the sound icon, computer mutes/unmutes correctly.
Also when I try to change the volume with fn+f11/f12 I see the volume level thingy changing in the middle of the screen but sound does not change as well. However, again, I can mute/unmute with fn+f10.
Similar things happen when I try from Setting > Sound. Under this menu in the "Choose a device for sound output:" list I only see "Speakers - Built-in Audio".
Another thing, if I change the sound in a player (let's say youtube) sound changes.
I tried these two but they did not help.
PS: Just to make it clear, this is the first time I installed any Ubuntu version on this laptop. I mean, I do not say "it was working and got broken after I installed 18.04"