Running Logic Pro 9.1.8 on Mountain Lion 10.8.3, the core system audio crashes completely almost every time. There are a few times when it will remain functioning normally and smoothly for an extended period of time, however, that does not happen often and it seems to be almost random. Once the audio has crashed, the icon in the status bar becomes grayed out, no sound comes from the built-in speakers, nor from headphones. After the crash, the system will seemingly function perfectly fine, of course without sound, until I try to quit Logic, at which point it becomes completely unresponsive and I have to do a hard shut down. I've tried everything from Terminal command lines, clearing .plists, clearing crashes, starting in Safe Boot, checking if its an issue with my administrator account settings, repairing disk permissions, /sbin/fsck -fy command line in single user mode, all to no effect. It seems like this also happens when I use Photo Booth (the audio crashes). Several times after starting the system up again after doing a hard shut down, I have found that after the Apple logo remains and the spinning wheel icon has gone, the single-user mode screen (black with white command line text) appears on the left side of the screen, as though it is coming through the regular start up screen, with every new line of text.
Every now and then I have seen a message pop up when opening Logic stating that there is an error with the core audio driver, with a code that I believe is something like "2549" (I'm not sure if this is it, it hasn't happened in some time).
Any help regarding this would be appreciated, as I believe I have looked everywhere on line for an answer, to no avail.