This may be slightly off-topic (and it's admittedly an older incident), but the fiasco with the Aegis missile cruiser, the USS Yorktown, often comes to mind when I read of high-value or mission-critical systems using Windows of any kind. Sadly, the Yorktown is certainly not unique with respect to major projects relegated to using Windows OSes- it just happens to be a particularly vibrant example of the potential results.
https://gcn.com/Articles/1998/07/13/Software-glitches-leave-...