If after disabling the notifications through Skype (version 5.0 or older), the notification boxes keep poping up in your MAC, then you might have Growl instaled and need to need to modify the preferences from there, read the following guide below
How to Disable Skype Notifications in Both Windows and MAC
- In your Skype Menu bar go to >> Tools >> Options >>and once you see the vertical navigation bar click on Notifications (red flag icon), and uncheck all the boxes there. Remember that there are also submenus where you can deselect the sounds or just mute them all to stop Skype Notification Settings.
Just for MAC Users, Turn Off Skype Notifications when Using Growl
This doesn’t help with Snow Leopard users but the first solution works anyways.
- Go to Apple Menu >> System Preferences >> Other >> Growl >> Applications >> Skype >> Configure >> Notifications >> Deselect Skype