Microsoft KB Archive/830957

= USB Device Does Not Initialize at Startup or Windows XP Stops Responding at Startup or Shutdown =

Article ID: 830957

Article Last Modified on 11/3/2003

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APPLIES TO


 * Microsoft Windows XP Professional Edition
 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Tablet PC Edition

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Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry



SYMPTOMS
When you start or shut down your Microsoft Windows XP-based computer, either of the following behaviors may occur:
 * A Universal Serial Bus (USB) device (for example, a USB mouse or a USB keyboard) may not initialize when Windows XP starts.
 * Your computer may appear to stop responding (hang) when Windows XP starts or shuts down.



CAUSE
These behaviors may occur if all the following conditions are true:
 * Your USB device is connected to your root USB hub.
 * You have manually added the SelectiveSuspendEnabled REG-BINARY value to the Windows registry.
 * Your USB device does not support the SelectiveSuspendEnabled feature.



WORKAROUND
Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To work around this behavior, delete the SelectiveSuspendEnabled REG-BINARY value from the Windows registry for your USB device.

To do this, follow these steps:  Click Start, and then click Run. In the Open box, type regedit, and then click OK. Locate the following key:

Where  is the vendor ID and the product ID of your USB device, and   is your USB device number. Click Device Parameters, and then click the SelectiveSuspendEnabled REG_BINARY value. On the Edit menu, click Delete. Click Yes when you receive the following message:

Are you sure you want to delete this value?

</li> On the File menu, click Exit.</li></ol>

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MORE INFORMATION
In Windows XP, USB can support the Selective Suspend feature. A driver that supports the Selective Suspend feature can turn off the USB device that it controls when the device becomes idle, even while the computer remains in a fully operational power state (S0).

For example, a driver can idle the host controller, empty USB hubs, and certain USB devices that the operating system supports. Selective suspend conserves battery power in laptop and Tablet PC computers. Typically, USB controllers use much battery power, even when no devices are attached to the computer.

Keywords: kbprb KB830957

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