I've had problems with the latest version of VT becoming unresponsive. This afflicts both computers I've installed the software on, a desktop and a laptop. What happens is that during the scanning/updating process, the application GUI goes a little funky (as I recall some of the items in the List panel vanish, but I don't have a way to verify the symptoms right now). Besides that, the program does not respond to any mouse clicks, and the dock icon's contextual menu says "Application has stopped responding" (or something similar). It doesn't happen every time, I would say about every 3rd or 4th time I launch it. VT seems to be sensitive to launching other apps or doing other things with VT is updating its list.