Hi Jon,
Sorry to hear you’re having trouble (and like Max said, do email support for guidance on how to deal with this! the following is only me trying to be semi-helpful in the meantime)
There is unfortunately no silver bullet (or definitive answer) because EMI gremlins like to live in the specificities of your setup / power distribution. Some folks (including yours truly) basically never experience an EMI-related disconnect even though they did not pay attention to grounding and things like that. For those that do have such issues, the #1 culprit is static from the dust collection (and/or shopvac itself), and grounding the hose goes a long way. For grounding the Shapeoko itself, have you seen Liam’s thread/tutorial videos ? We referenced them very recently in this thread. I’m afraid there is no skipping school if you want to do this only once though. Trial and error is incredibly frustrating when dealing with EMI goblins, so a “scientific” approach helps.
You won’t be able to find a log indicating the cause of the disconnect, basically because the disconnect is the computer/CM not succeeding is communicating with the controller, and it can’t know why exactly once the link is down.
Until you hear back from support, grounding your dust collection hose is your best bet (ideally, get an antistatic one with the copper wire embedded in it, and ground one end of the copper wire to a known-good grounding point I’m not too familiar with US outlets and how to actually do this on those, but there are some threads about it, and folks will likely chime in with advice)