Issue

When you plug in the USB cable from the LT-2D3D/LT-55 XL a notification bubble appears in the lower right corner of the screen.

Unknown USB Device (Device Descriptor Request Failed)

Cause

The driver that is used to allow the encoder (how the laser measures angles) has been either updated to an incorrect Microsoft Driver.

Solution

Uninstall bad Microsoft driver and install proper CDM driver

  1. Click Start
  2. Search for Device Manager
  3. Locate the USB device with the incorrect Microsoft driver. It will have an icon next to it of a yellow triangle with an exclamation mark inside of it
  4. Double click on the USB device and click the Driver tab at the top of the window. On the Driver tab, you sould see:
    1. Driver Version: 6.3.9600.17238 (or a similar number to that)
  5. Click Uninstall
  6. Click OK. Device manager uninstalls the device
  7. Follow instructions to install the CDM driver
  8. Right-click your computer name in Device Manager and click Scan for hardware changes
  9. Device manager scans your system and automatically reinstalls your device.