UserPreferences current beepEnabled:false
you can put this into the startup .rc-file or evaluate it from a workspace.
It can also be turned off via the settings dialog; however, the flags are a bit hidden: there are 3 found in the "acoustic signals" section AND another on in the viewStyle setting - I admit, that is stupid and will change...
Turn off both to stop annoying others in the office and to avoid VMWare from crashing if it has a sound-driver problem
