Consider the following scenario:

• You have a Windows Vista-based computer that uses an Open Host Controller Interface (OHCI) host controller. This OHCI host controller is Institute of Electrical and Electronics Engineers (IEEE) 1394-compliant.
• You have two IEEE 1394-compliant storage devices.

In this scenario, you may experience one of the following issues:

• When you start the computer and connect the first IEEE 1394-compliant storage device to the OHCI host controller, the device is loaded correctly. However, when you connect the second storage device, this device never appears in Device Manager. Additionally, the first device disappears from Device Manager.
• When you connect the two IEEE 1394-compliant storage devices before the computer is started, neither device appears in Device Manager after you start the computer.

Open Host Controller Interface: A Firewire card that supports a standard interface to the PC and can be used by the OHCI FireWire drivers that come with all modern operating systems.

Consider the following scenario. You connect a universal serial bus (USB) speaker to a Windows Vista-based computer. The audio sounds clear. Then, you connect another USB device to the computer. For example, this USB device may be a USB mouse, a USB keyboard, or a USB game controller. In this scenario, the audio from the USB speaker is now distorted. This problem occurs when the computer uses an Open Host Controller Interface (OHCI) controller.

When you resume a Windows Vista-based computer from sleep, you may experience unexpected behavior from a USB device. This problem occurs on a computer that uses Open Host Controller Interface (OHCI) host controllers. This problem may cause unexpected behavior.