- Registration time
- Last login
- Online time
- 394 Hour
- Reading permission
What is USB enumeration?
When you connect a USB device, the system should recognize it and load a proper driver in a process called USB enumeration, but if this fails in OS X, then you might see little or no activity from the device and a repeated message in the OS X console that states the system was not able to enumerate the device.
USB enumeration is a fairly complex process that involves detecting the device, identifying its speed, getting its configuration and description information, assigning port addresses and loading drivers for the device, but to the lay person it essentially means the device is detected and properly loaded for use. If an enumeration error occurs in OS X, the system will try several times to get the necessary information from the device for loading it, but if not then the system will eventually give up.
An enumeration error will generally happen because the device is not working, a driver is corrupt, or a communications error is occurring. In these cases, there are several things you can do to address the problem:
-The device is not working
Try using an external power adapter if the device will accept one to keep from using the less-reliable bus power from the computer. Additionally, the device might need to be reset, which can sometimes be done by unplugging it for a while; other times it may require depressing a special button.
Try updating the driver from the manufacturer's Web site, or uninstall a previously downloaded one and rely on the generic ones in the device or which shipped with the OS.
Try unplugging the device and plugging it back in, or try cleaning the cable and the device's contacts to ensure there is proper communication.
You can clean the device's contacts or try using a different USB port on your computer and swap out the cable for a new one, since kinks or other faults in the cable could result in poor communication with the device.