I am assuming this update is the cause. But it has been occurring since the last update, when restarting after a nightly shutdown, the desktop appears and freezes. The task bar has a spinning symbol says it is trying to start something. I can;t get to task manger. Have to restart and it seems ok from that point. Got this error in performance manager DNISp50a64 protocol driver. My system is a windows 7 pro. Not sure what has happened could it be a corrupted driver? Thanks for your help.