I think that solved the problem. My only hesitancy is that today the failure mode is not a power off but rather a message saying my PC has an error and can’t load (forgot the exact wording). Regardless, with the BIOS change, I’ve successfully booted 4 or 5 times. I suspect the root cause of the fail...

Thanks, I’ll give it a try.

That reference describes setting a USB port in BIOS to “no detect”. Does that mean the port becomes useless?

I seem to have the same problem. In my case if I power up NUC and the Powerbox with the two connected via USB, the NUC will power off. If I connect the USB only after NUC comes up, everything works fine. Doesn't seem to matter which NUC USB port is used nor how the cable is routed. Nor does the exac...