I had now been on holiday for a week and, as my first task back in office, I asked my colleague how the application had performed during my absence. There had been no crashes.
The only thing I did was disable the PlaySoundFile VIs.
Thank you very much, @pincipanter.
Implementing log files on each MHL, EHL, etc. took up so much of my debugging time. Shame on you, NI. I am very disappointed.
