If you are using Digital Performer 2.4 or later with a Digidesign card and Sound Designer 2, please be aware of the "Play Audio in Background" feature now available in the Preferences window. If "Play Audio in Background" is enabled, you will not be able to launch Sound Designer 2 using the "Open in Waveform Editor" feature. If you disable this preference, both Digital Performer and Sound Designer 2 can be running at the same time. The application in the foreground will be able to access the hardware.