Writing NaN to the duty cycle input of the DAQmx Write (Counter Frequency) VI will cause an abrupt crash of LabVIEW 17.0f2 (32-bit). So far it seems hardware independent. It will even happen with simulated cDAQ hardware. For example, create a cDAQ-9189 or 9178 chassis and add a 9401 or 9485 module. Run the attached VI with one of the counter channels selected. Click the Send NaN button and LabVIEW will crash. I realize NaN is not a valid input for duty cycle, but at worst it should generate an error rather than take down the entire application. Took me a while to figure this one out, but luckily the crash logs generated when running an EXE were pointing me to the VI that was causing the crash.
