Microsoft KB Archive/314634

= Windows XP or Windows Server 2003 does not detect your new USB device =

Article ID: 314634

Article Last Modified on 12/3/2007

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APPLIES TO


 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional
 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)
 * Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)

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This article was previously published under Q314634



Notice
These methods are intended for advanced computer users. If you are not comfortable with advanced troubleshooting, you might want to ask someone for help or contact support. For information about how to contact support, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/



Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756 How to back up and restore the registry in Windows XP and Windows Vista



SYMPTOMS
When you connect a new USB device to a computer that has no USB devices, Windows XP and Windows Server 2003 may not detect the new device.



CAUSE
This problem may occur because, when no device is connected to a USB port, the USB driver sets the Open Host Controller Interface (OHCI) controller to suspend. When the OHCI controller is in a suspended state, it cannot always detect when you add a new USB device to your computer.



Step 1
To resolve this problem, obtain the latest service pack for Windows XP. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

322389 How to obtain the latest Windows XP service pack

Step 2
After you apply the latest Windows XP service pack, you can create a new registry entry that prevents an OHCI controller from entering Suspend mode.

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

Disable the Selective Suspend feature of the USB hub driver. To do this, follow these steps:
 * 1) Click Start, click Run, type regedit, and then click OK.
 * 2) Locate and then click the following key in the registry: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\USB
 * 3) On the Edit menu, point to New, and then click DWORD.
 * 4) Type DisableSelectiveSuspend, and then press ENTER.
 * 5) On the Edit menu, click Modify.
 * 6) Type 1, and then click OK.

Note If the DisableSelectiveSuspend registry entry is not present, you must create it. This setting affects all USB host controller drivers in the system.

If the value of the DisableSelectiveSuspend registry entry is set to 1, the Selective Suspend feature is disabled. Additionally, the Allow the computer to turn off this device to save power check box does not appear on the Power Management tab for the USB Root Hub.

Windows Server 2003 users
Create a new registry entry that prevents an OHCI controller from entering Suspend mode.

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

Disable the Selective Suspend feature of the USB hub driver. To do this, follow these steps:  Click Start, click Run, type regedit, and then click OK. Locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\USB

 On the Edit menu, point to New, and then click DWORD. Type DisableSelectiveSuspend, and then press ENTER. On the Edit menu, click Modify.</li> Type 1, and then click OK.</li></ol>

Note If the DisableSelectiveSuspend registry entry is not present, you must create this registry subkey. This setting affects all USB host controller drivers in the system.

If the value of the DisableSelectiveSuspend registry entry is set to 1, the Selective Suspend feature is disabled. Additionally, the Allow the computer to turn off this device to save power check box does not appear on the Power Management tab for the USB Root Hub.

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STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section. This problem was first corrected in Windows XP Service Pack 1.

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