In Windows 7 a red 'X' may appear over the speaker icon in the notification area even though audio output functions correctly

Symptoms:
Consider the following scenario:  After installing or upgrading to Windows 7, the speaker icon in the notification area of the system tray shows a red 'X' indicating that audio output is not working.  In addition, hovering the mouse over the speaker icon will show a tooltip indicating that the Audio Service is not running.  However, the Audio Service is running and audio playback works correctly.
Cause:
This behavior can sometimes occur during periods of heavy disk activity when booting to the Windows desktop.  In this situation, it may be possible that even after the Windows Audio Service has been started, the speaker icon status in the notification area does not get refreshed to indicate that audio playback is functional.
Resolution:
In most cases, this behavior is temporary and the red 'X' will disappear when:

- Windows 7 has finished booting to the desktop and hard drive activity has decreased.
- The first time the user clicks on the speaker icon to change the audio playback volume level.

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More Information:
An example of where this behavior might be encountered is after Windows 7 Setup and OOBE has finished and the user reboots to the Windows desktop.  During this time, heavy disk activity may be encountered as Setup finishes any final tasks and startup applications are initialized.
behavior is cosmetic in nature and does not affect the performance of Windows.