Why are there no sounds located in the Library/Sounds folder in Home Directory? My Mail alerts, etc

Question

Why are there no sounds located in the Library/Sounds folder in my Home Directory? Since upgrading to Mountain Lion most of my sounds are not working, in my Mail alerts, etc.

Answer 1

Did you put any sound files there? Because if you didn't, that will explain why it's empty.
The ~/Library/Sounds folder is where any sound files that you add go, and they are only available to you as the "logged in" user (if you have other users with their own accounts, they each have their own ~/Library/Sounds folder). Apple doesn't put anything there.
The sounds that come with Mac OS X will either be in the /Library/Sounds folder (which is the shared location for all users) or the /System/Library/Sounds folder (don't mess around with anything in the /System folder!).
But I doubt your problem has anything to do with the sound files. Try deleting your sound preferences file, or even just clicking around in the Sound system preferences until they start working again (seriously - I had one Mac that had some audio problems after upgrading, and just turning things off and on a few times eventually worked. It seemed somehow tied to Dictation, so try twiddling those settings too).