Hello, rmanley, were the Parallels Tools upgraded normally during last build installation? please, have a look at Start -> Control panel -> System -> Hardware -> Device manager isn't there any problem with USB or audio device? You can try to reinstall the correspondent driver or just roll it back to the previous that worked. One more workaround is to open virtual machine's configuration (when it is stopped) and remove the USB device. You can add it back afterwards and see if your USB audio works again. But be cautious as it can affect other USB devices which now work OK. Finally, open the Start -> Control panel -> Administrative Tools -> Event viewer and see if there are any warnings/errors under System and Appications tabs concerning the audio problem you have.