I'm having a problem with audio my mac mini. It's saying there is no audio device. The system is an older model intel mac mini running mountain lion. In System prefs/sound, it says 'no output devices found' and the same for input. Utilities/audio devices says 'no devices found on the system' In about this mac, devices show nothing. There is something saying 'intel high definition audio' but in the pane below it just says 'Audio ID: 0' [not really sure what that means] Obviously therefore, no audio apps will output any audio and the volume control on the menu bar is greyed out. When I start the computer I hear no chime. Can anyone suggest anything? I've tried all the usual stuff such as reboot, repair permissions, plugging a jack in and out and they didn't work. I tried deleting the com.apple.bezelservices.plist which didn't work. I have a little usb audio hub which does work for the moment, however I've just bought a nice D/A converter which works straight off the optical out so I want to use that. I tried reinstalling OSX. As I had the Mountain lion image in my app store purchases I ran that. It did say it was installing OSX but my system looks the same so I'm wondering if it did enough. Is it worth zero-ing out the disk and doing a fresh install off a drive?