Hi, thanks for your reply!!
I believe you're refering to the link General Troubleshooting - Pro Tools LE Mac , since that's the closest match to my system.
As suggested there, I should delete these files and restart the system:
* com.digidesign.CoreAudioManager.plis
* com.apple.audio.AudioMIDISetup.plis
* com.apple.midi.a bunch of numbers and letters.plist'
* com.apple.audio.audiomidisetup.plist
However:
a) I cannot locate the 2 pathes suggested ("Mac HD > Users > (Your User Name) > Library > Preferences" and "MacHD>Users>your account>Library>Preferences>By Host")
b) I do find some "com.digidesign" and "com.apple" files at "Mac HD > Library > Preferences" but, still, cannot find ANY of the files suggested to be trashed.
Thanks!!!
Mac OS X Lion 10.7.1