VLK, I get the message in the attachment. A few instances of unable to kill, but usually can. Did not happen with Comodo firewall, so definitely an interaction between avast! and OA. Trying minimum configuration now to see if it stops: OA with just Program Guard and Firewall, avast! with just standard shield and network shield. That seemed to work before OK, so will let it run for a while and see what happens. BTW, happens on two different computers with Vista and avast! First happened on computer with OA, not on computer with Comodo. Switched main computer to OA, now happens there also.