I noticed that special alert 2 which I have set to C'Thun: You Will Die! is not playing any sound. In the options all other alerts play when I select them except for this one. I updated to the lastest release r174 and the same thing is happening. I've also gone all the way back to r136 and I still don't hear it. I definitely remember it working about a month ago, so I don't know how that's possible. I've disabled all other addons and still no luck.

def hasn't been changed by us but maybe classic isn't using a diff sound path from retail anymore? i assume this is on classic?

Sorry, this is on retail. I should have clarified. I have since realized the sound is completely gone from my game. I used another addon to try and play the sound file and it couldn't play it either