--- a/src/eric7/MicroPython/MicroPythonWidget.py Wed Nov 09 09:42:19 2022 +0100 +++ b/src/eric7/MicroPython/MicroPythonWidget.py Wed Nov 09 10:37:21 2022 +0100 @@ -498,10 +498,11 @@ vid = self.deviceTypeComboBox.itemData(index, self.DeviceVidRole) pid = self.deviceTypeComboBox.itemData(index, self.DevicePidRole) - self.__device = MicroPythonDevices.getDevice(deviceType, self, vid, pid) - self.__device.setButtons() + if deviceType or (pid is not None and pid is not None): + self.__device = MicroPythonDevices.getDevice(deviceType, self, vid, pid) + self.__device.setButtons() - self.connectButton.setEnabled(bool(deviceType)) + self.connectButton.setEnabled(bool(deviceType)) @pyqtSlot() def on_checkButton_clicked(self):