Nuendo halts and freezes recording from Dante

We are recording up to 30 channels of 48K over a Dante network thru a Yamaha AIC128-D card into Nuendo 7, and it is synced with video. We have gotten recording halts sporadically for several months. First the halts came with the message “Recording error: Audio dropout detected” but we found no dropouts in the wav files recorded on another machine. In August we got several recording halts with the message “Too many tracks recording” with only 14 tracks. The two halt problems happened in separate time periods. They stopped without figuring out anything we did.
This month Nuendo froze 3 times during recording. Nuendo could not be shutdown even though the mouse and other applications continued to function. So the DAW has to be rebooted.
We are not sure whether it is a problem with the Dante stream, the hardware or Nuendo. Does anyone know how to track down the cause of such a problem?

Sounds like a failing hard disc.