No device selected

Please select a device before connecting.

DEVICE_NOT_SELECTED

Symptoms

  • Clicking connect shows "No device selected".
  • The device dropdown shows probes but none is highlighted.

Likely causes

  • More than one probe is attached and MCUHex will not guess which one to use.
  • The previously selected probe was unplugged, clearing the selection.

How to fix it

  1. Pick a probe from the dropdown

    Open the device selector in the footer and choose the probe you want. Each entry shows the probe type and serial so you can tell boards apart.

  2. Connect

    With a device selected, click connect. If the list is empty instead, see the "No debug probe detected" guide.

Related errors