Here’s how to solve the USB3 not being detected (Front or Rear ports) on HP’s Z420

Make sure the ports are powering any device (the devices might not be detected at all).

Plug those devices on the USB 2 ports to make sure they work and they’re detected by windows.

This issue may arise even when those USB 3.0 ports were working before and suddenly they stopped doing so.

  1. Download these drivers:
    http://www.ti.com/product/TUSB7340
  2. Install them
  3. Restart the machine
  4. Everything should work now.