Can;t believe it. The startup sound has stopped working again. Checked that startup command and it is unchanged. It's late now and will get back to this tomorrow.
Running Linux Mint MATE on 2 desktops + Linux Mint Xfce on Netbook + Cinnamon VM on 3rd Desktop
I upgraded from LM 19.3 Mate to LM 20.0 Mate. No audio, period.
After trying lots of "fixes', nothing worked.
My fix:
Go to Menu/Sound & Video.
Delete Pulseaudio, Sounds, and QasMixer (if listed).
Reboot.
All sounds now work.
Sound icon in lower-right corner by clock is gone. Using keyboard volume keys works fine.
Reinstall Pulseaudio and QasMixer.
Looks like LM20 needs an overhaul.
"Tolerance is the refuge of men without conviction."
"Common sense is not so common" - Voltaire