This probe has no driver

Windows sees the probe, but no WinUSB driver is bound to it, so pyOCD cannot open it. The probe and the cable are fine.

PROBE_DRIVER_MISSING

Symptoms

  • The probe is listed in MCUHex greyed out and marked [no driver]; connecting says the probe has no driver.
  • Device Manager shows the probe with a warning mark, as "STM32 STLink" or "ST-Link Debug".
  • pyOCD-based tools report no probes at all, while the probe’s LED is on.

Likely causes

  • Windows has no driver for a debug probe out of the box. MCUHex opens the probe through libusb, which only sees an interface bound to WinUSB; a probe bound to nothing never reaches it.
  • A stand-alone ST-Link V2 dongle and the ST-Link on a Nucleo or Discovery board both arrive like this on a machine without ST’s tools.

How to fix it

  1. Bind the probe to WinUSB with Zadig

    Open Zadig with the probe plugged in. It lists the probe by itself (USB ID 0483); pick it, make sure the target driver reads WinUSB, click Install Driver, then replug. If STM32CubeIDE or STM32CubeProgrammer is installed you can skip this — their driver already does it. A J-Link is different: install SEGGER’s J-Link Software Pack instead.

    Download Zadig ↗SEGGER J-Link Software Pack ↗

    Zadig with “ST-Link Debug (Interface 0)” selected, USB ID 0483 374B, and WinUSB as the target driverZadig reporting “The driver was installed successfully”

  2. Replug and refresh

    Unplug the probe, plug it back in and click the refresh icon next to the device list. The row turns from greyed out to selectable and connects.

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