Using an older version, I couldn't get the sound to play if I
downloaded e-mail manually. One user (using an older version)
couldn't get a sound to play if the .wav file was in "My
Documents." In older versions, there might also have been a problem
if you had over 300 (?) messages in the New mail folder.
Again, in the older version, there was a setting under
Tools/Options/Advanced/Advanced Settings/Refresh the new mail
folder every __ secs, where this value should be set to something
small (but not negative); I had it set to 3 seconds. I don't know
if this option still exists in the new version, or where it might
now be located.
The options I enabled in versions 3.12c were:
[x] Place an icon in the Windows system tray
[x] Animate the icon (flap its wings) when new mail arrives
[x] Hide the Pegasus Mail taskbar entry when minimized
[x] Play a new mail alert sound
My e-mail address works as is.