Could there be another camera-related program running at the same time? If there is such a program, it could well be the culprit.

Thank you, Stas. I think that was the issue. EOS Utility was in the start up items list. It didn't actually start up in the full sense but I guess it was running in ...

Hi Stas, For what it's worth I have a similar problem on a Mac. I can't figure out the correct combination for quitting the program without it hanging up. Currently I turn off live view, quit Remote and then turn off the camera. Sometimes that works and sometime not. If I don't quit in that sequence ...