On a Windows Vista-based computer that has an Intel I/O Controller Hub 9 (ICH9) mobile chipset and a High-Definition Multimedia Interface (HDMI) adapter installed, you connect an HDMI audio device to the computer. After you disconnect the HDMI audio device, you open the Sound Playback dialog box. Then, you may notice one of the following problems:

• The Digital Output Device (HDMI) High Definition Audio Device entry still displays a Working status, and this device may be selected as the default HDMI device.
• The Digital Output Device (HDMI) High Definition Audio Device entry does not always appear in the Sound Playback dialog box after you disconnect the HDMI device. However, the HDMI device may appear after you close the Sound Playback dialog box and then open it again.
• The Digital Output Device (HDMI) High Definition Audio Device entry displays a Working status, even when an HDMI device has never been connected to the computer.

This problem may occur with some third-party drivers and also with the Microsoft in-box Digital Output Device (HDMI) High Definition Audio Device drivers.