I also have no incoming mail sound since upgrading to El Capitan. I'm now on 10.11.2. I tried to create the suggested script but I get this syntax error when trying to play it:
error "Mail got an error: sh: -c: line 0: unexpected EOF while looking for matching `''
sh: -c: line 1: syntax error: unexpected end of file" number 2
any ideas?
The script I created is: (where MY NAME is the name of my user file)
tell application "Mail"
do shell script "afplay '/Users/MY NAME//Music/iTunes/iTunes Media/Music/Unknown Artist/Unknown Album/you've got mail-hanks.wav'"
end tell
If I put this path into Go To in finder, it plays the sound, so I don't understand why this is not working for me.
😟