Just yesterday, I noticed that I wasn't hearing my New mMil sound though new mail was arriving. I also wasn't hearing the crunch of trash being removed. I went into System prefs>Sound and found that none of the effects would work. I also noticed that the "Play through Internal speaker" optioon was greyed out.
All other sounds work fine...iTunes, videos, etc.
I apologize if this is the wrong forum, but if any of you have any suggestions to help me get my sound effects back, I'd appreciate it.
If it helps, I tried using headphones and all the sounds work. The sound in system prefs shows playthrough headphones, but it, too is greyed out. if i remove the headphones, it goes back to Internal speakers, but it's greyed out. Shouldn't that be accessible?
They seem to be working now that I inserted and removed some headphones. But what bothers me is that greyed out selection in the Sound System Prefs. Shouldn't that be selectable?
Yes, I've been having this problem for a while now too. It just started in the last few days and I don't know how. Yesterday I restarted the computer and the sounds came back for a while before disabling again. The option to play alerts and sound effects is also grayed out. I trashed the files you listed, and it worked for the other guy, so I hope it works for me.