Conversion start error

I have a problem (error) I have not encountered before, and a search for process not running did not turn up anything relevant here.

I have been using MCEB intermittently for a while (OTA via a HD Homerun) and recently began using it regularly when I did away with satellite TV. I have paid version 2.4 beta 7 running on a Win7-64 Ultimate box, and the paid (donator) version of Comskip. After processing, it drops the file onto a Windows Home Server 2011 box, where it is processed by Plex. Everything had been going mostly good until today.

I use PlayOn for streaming and Tablo for OTA shows. I had set an hour long show to record during my overnight PlayOn queue, and at 4:01 AM it showed as being processed with no errors. When I tried to watch it, the length was only 5 minutes.

Several other hour long streaming shows processed OK during this time. I manually added the show from my archive folder (it was over an hour long and the file played OK on my computer) and it looked like it was processing OK, but then it never turned up on my server. The log said this:

_ERROR> 2017-08-01T16:23:44 MCEBuddy.AppWrapper.NVidiaQuery --> Unable to start process_
_Process with an Id of 20036 is not running._

Any ideas on what happened? I have not made any changes to either computer between 4:01 AM and now.

Please attach your conversion log

What I posted was the entirety of the log.

Rebooted the machine and it processed OK.