This article provides some troubleshooting steps applicable to USB devices.

ASP lists the USB devices that are connected as well as which device they may be connected through. By using ASP, you can get a good representation of the USB devices connected to the computer without having to trace all the devices and their connections.

The following steps may assist you in isolating the cause of a USB issue:

1. Check to make sure you have the latest firmware update for your computer. Apple has released firmware updates that may help to resolve USB issues. Search the Apple Software Updates Web site at http://www.apple.com/swupdates for relevant updates.

2. Try unplugging and replugging the USB cable on device that is having the issue. If you have another USB cable, try it also. Verify that the third-party device is plugged into power if it is self-powered.

3. Use Apple System Profiler to verify the device is seen by the Macintosh. If it is, the issue is usually software in nature because the Macintosh hardware can see the device. Continue on to step 4. If the device is not seen by Apple System Profiler, it may require service and the service representative for the device should be contacted for further information.

4. Restart the computer holding down the Shift key to disable any non-Apple extensions. Once the computer has started up, try the device again. If it works, you may not need the software supplied with the device, use the Extensions Manager control panel to enable all the extensions except for the USB device in question and restart. If the device fails, continue to Step 5.

5. Verify that the USB device driver software is installed and active. If the software is active and the device shows up in ASP but is not working, reinstall the software. First check the Web site for the device to see if there is an updated version of the driver.