Advanced troubleshooting tips for general USB problems in Windows XP

This article describes advanced troubleshooting tips for universal serial bus (USB) devices in Windows XP.

If you have a problem with a USB device, try these methods first:

1. Unplug and then plug in the device.
2. If the computer prompts you for a device driver, read the information that was included with the device, or visit the manufacturer's Web site to see whether a driver is available.
3. Run Windows Update to obtain the latest fixes for Windows XP. When this is complete, plug in the device to see whether it is installed correctly.

If the problem persists after you try these three methods, you can use the "Advanced troubleshooting" section to try to resolve the issue.

Advanced troubleshooting

This section is 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 do this, visit the following Microsoft Web site: Because USB devices are Plug and Play devices, there is little that you can do to control or configure them. However, you can trace most USB problems to one of the following conditions:

• Malfunctioning or incorrectly-configured hardware
• Malfunctioning, incorrectly-configured, or missing device driver
• Mismatched cabling
• Out-of-date firmware or basic input/output system (BIOS)
• Incorrectly-configured root hub

You can use the following troubleshooting tips to check for each of these conditions to help you resolve USB device issues.

Malfunctioning or incorrectly-configured hardware

Typically, if you plug a malfunctioning or incorrectly-configured device into a USB port, it causes the computer to stop responding (hang). In most of these instances, you must physically turn off the computer and turn it back on to reset the bus. Be aware that it may be more difficult to identify which device is malfunctioning or is configured incorrectly. If another computer that you know is working correctly is available, try to plug the device into that computer to see whether you encounter the same issue.

If the device is plugged into a secondary hub, unplug the device from the hub, and then plug the device directly into the root hub.

Many hardware problems (such as high or low power, bandwidth shortage, malfunctioning or incorrectly-configured firmware, and so on) can cause issues to occur.

Check Device Manager to be certain that the root hub is functioning correctly. If the root hub is displayed with an exclamation point (!) in a yellow circle, verify that the BIOS is assigning an interrupt request (IRQ) to the root USB controller. This is required for the device driver to be loaded. For more information about how to use Device Manager to troubleshoot hardware issues, click the following article number to view the article in the Microsoft Knowledge Base: If no devices work when you plug the devices into the root hub, verify that the power requirements of the bus are not being exceeded. USB devices can draw a maximum of 500 milliamps for each connection. If a device tries to draw more power than this, the specification recommends that the computer should be able to disable that specific port until the computer power is cycled (this is known as "suspending" the port). In addition, if the device draws less than 50 milliamps, the port never becomes active.

Check the Power tab in USB Root Hub properties to check the power usage of the USB bus.

Malfunctioning, incorrectly-configured, or missing device driver

When you plug in a USB device, the computer should load and then configure the device without ever requesting a device driver (assuming that the device falls within the defined and supplied class drivers). If the computer prompts you for a device driver, check with the manufacturer of the device to determine whether a driver is available.

Mismatched cabling

There are two types of USB cables, high speed and low speed. Low-speed cables differ from high-speed cables primarily in their shielding. If you plug a high-speed device into a low-speed cable, you can cause signal distortion over long distances.

Verify the USB chain is working correctly to be certain that a device that requires the ability to draw power from the hub is not plugged into the chain on the other side of a non-powered hub. This causes that hub and all devices down the chain to be suspended. If the hub is a powered hub, verify that the power supply for that hub is configured correctly.

Out-of-date firmware or BIOS

The key to all USB devices is the firmware. The USB device's firmware contains all information about the device. A port is not reset until all descriptors in the firmware have been loaded and verified by the root hub. This is important because it applies to items such as printers and modems. Make sure that you have the most up-to-date firmware that is available for both your computer's BIOS and each device.

The symptoms of malfunctioning or incorrectly-configured firmware might be unusual. Typically, when you remove and then re-add a USB device, the device becomes available again. However, the device may be displayed as a second instance of that device, and load itself as such in Device Manager. If you see duplicates of a device, verify that you have the most up-to-date firmware for that device. This issue is common with USB printers and modems. A similar issue that has the same cause occurs when a device loads a device driver, and then adds a second device for which there seems to be no driver. The second device is displayed with an exclamation point in a yellow circle in Device Manager. The device may work correctly. However, you cannot remove the "ghost" device until you unplug the parent device that seems to have generated the ghost device. Also, you may be able to resolve this issue by updating the firmware or the device driver for that device.

Incorrectly-configured root hub

USB controllers require that an IRQ be assigned. The IRQ line is assigned in the computer's BIOS, and usually IRQ 9 is assigned.

Remove and reinstall all USB controllers

To remove and reinstall all USB controllers, follow these steps:

1. Click Start, click Run, type sysdm.cpl in the Open box, and then click OK.
2. Click the Hardware tab.
3. Click the Device Manager button.
4. Expand Universal Serial Bus controllers.
5. Right-click every device under the Universal Serial Bus controllers node, and then click Uninstall to remove them one at a time.
6. Restart the computer, and then reinstall the USB controllers.
7. Plug in the removable USB storage device, and then test to make sure that the issue is resolved.

If the articles listed here do not help you resolve the problem or if you experience symptoms that differ from those that are described in this article, search the Microsoft Knowledge Base for more information. To search the Microsoft Knowledge Base, visit the following Microsoft Web site:Then, type the text of the error message that you receive, or type a description of the problem in the Search Support (KB) field.