Rather than trying to figure out what other file it is, wouldn't it be simpler to uninstall Defender and MSE (temporarily) and install Avira or Avast or whatever. See if the problem happens then. If it doesn't, I would call AC, and tell them to remote in and fix it. Period. My guess is with an uninstall and reboot, you won't have the problem. Then with any other AV programs, I doubt you will have the problem.
Good luck.
