The MMC (PCU) has a configuration file that tells it where to look for the NCK. If this file is corrupt or reset to defaults, it will look at the wrong address.

The Beast ran for another seven years—until the day they replaced it with a SINUMERIK ONE. But no one ever forgot the night the NCK went silent, and the clock almost ran out.

For fifteen years, it had run without a single NCK (Numerical Control Kernel) fault.