I muted all sounds on an Earlier version of Skype and I now need to umute them so I can hear calls coming in but I do not see an option to umute all sounds or enable all sounds in version 5.7 for Mac -- PLEASE HELP ME SOVE THIS.
On the menu bar go to Skype\Preferences\Notifications and select Details. Then you can select events and what sounds to play, or not play, for each event.
I have the same problem with version 5.8 of Skype for mac. Rwakeford's solution posted does not work. It seems like there's a glitch.