I spent 30 mins today trying to understand why the Visual Round Trip Analyzer (VRTA) or NetMon wouldn’t capture any data. After a lot of fiddling with network settings, Virus checkers and the like it turned out to be something very simple. NetMon has settings about how much disk space you should have free before it automatically stops capturing…yes I’ve got less than the default 2% free. After changing the setting it started working. Would have been nice if it has said, "automatically stopped, not enough free disk space" or something!