Windows Vista does not enumerate an IEEE 1394a device that you connect to the computer

When you connect an IEEE 1394a device to a computer that is running Windows Vista, Windows Vista does not enumerate the device. However, if you connect the same device to a computer that is running Microsoft Windows XP, Windows XP enumerates the device successfully.

Note An IEEE 1394a device may also be referred to as a FireWire device.

Windows Vista only enumerates a device that sets its link status to request enumeration. If an IEEE 1394a device does not report the correct status of its link, the IEEE 1394 stack in Windows Vista does not enumerate the device.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

To work around this problem, for non-compliant IEEE 1394a devices, configure Windows Vista to enumerate inactive IEEE 1394 devices. To do this, follow these steps:

1. Click Start
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   , type regedit in the Start Search box, and then click regedit in the Programs list.
   
   
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   If you are prompted for an administrator password or confirmation, type your password or click Continue.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{6BDD1FC1-810F-11D0-BEC7-08002BE2092F}\ControllerInstance
   In this path, ControllerInstance represents the controller instance number. For example, this number may be 0000.
3. On the Edit menu, point to New, and then click DWORD (32-bit) Value.
4. In the New Value #1 box, type EnumerateInactiveLink, and then press ENTER.
5. Right-click EnumerateInactiveLink, and then click Modify.
6. In the Value data box, type 1, and then click OK.
7. Exit Registry Editor.

You may be able to obtain a firmware update for the IEEE 1394a device to resolve this problem. To determine whether a firmware update is available for the device, contact the device manufacturer or the device vendor.

For information about how to contact computer hardware device manufacturers or vendors, click the appropriate article number in the following list to view the article in the Microsoft Knowledge Base:

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