When you examine the playback devices after you start a computer that is running Windows Vista or Windows Server 2008, some audio devices are missing or display the “Not plugged in” status
You have a computer that is running Windows Vista or Windows Server 2008. You examine the playback devices on the Playback tab in the Sound dialog box after you start the computer. Then, you notice one or more of the following issues:
- Some audio devices are missing.
- The status of some audio devices is “Not plugged in.”
- This problem typically occurs for HDMI devices that are set to be the default audio device.
- This problem may be resolved if you restart the computer.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB974868.