I tried disabling it but no change. I agree that it could still be interfering somehow, but I couldn't figure it out.
moderator: Thanks for the info.! Will ask a colleague who has Windows--she's out now, so probably not til Th. or Fri.--to try IE out on this challenge. Even though it's a bit early, just to ensure I don't forget, I'd appreciate a bump on this Fri. morning if you haven't heard back.
update: No other reports of issues. My boss tried it out. No IE, but she used Edge which I think in this case should be the same (ActiveX shouldn't be relevant, for example), and on Windows 10 it worked.