Continuing our series on user activity monitoring, today we look at something that is very hard to do in Vista and later, and impossible in XP and earlier — that is reporting on system idle time. The only way to accomplish this in Windows is to setup a domain policy to lock the screen after a certain amount of time and then calculate from the time the screen saver is invoked to when it is cleared. In XP and prior, however, the invocation of the screensaver does not generate an event so you are out of luck. In Vista and later, an event is triggered so it is slightly better, but even there the information generated should only be viewed as an estimate as the method is not fool-proof. We’ll look at the Pro’s (few) and Con’s (many). Enjoy.