I uninstalled and then ran the support tool to remove all vestiges.  Let the tool re-install, rebooted, and now I'm keeping an eye on things.  the first startup and scan had Malwarebytes appear to stop responding, but finished okay without crashing. A couple of items I neglected to mention: 1) The original problem was bad enough that it was actually preventing me from powering up the Surface or from rebooting. It would hang and require me to either kick off Startup Repair or dig into t