Perhaps the most commonly encountered problem with USB devices is enumeration failure. If a USB device fails to enumerate successfully it will appear in Device Manager with a problem code of 43, and will be listed as an “Unknown Device” If Windows was unable to identify the device before it failed enumeration. There are a number of reasons why a USB device can fail to enumerate, however the specific reason for the failure has not been easily discovered without using diagnostic tools such as USB ETW logging.
Windows 8 will now provide a problem description in Device Manager for USB devices that have failed to enumerate, and for USB hubs that have failed during operation. When one of these failures occurs, the USB device’s status on its “General” property page will display a problem description indicating what the failure was. Below is an example device status for a USB device that failed because it returned an invalid USB configuration descriptor. The problem description is highlighted.
The possible problem descriptions that can be returned for a USB device that failed enumeration in Windows 8 are:
The possible problem descriptions for a USB hub failure in Windows 8 are:
To resolve these errors a user should follow the steps outlined in the blog post What to Try When Your USB Device is an "Unknown Device". A USB device developer encountering any of these errors should investigate further using USB ETW logging.