Hi Orbiters...I've just added the SSU 4.2 to my Orbiter 2010 and it seems to work fine...I'm trying to run one of the scenarios....STS-120 and I can see the countdown clock counting down on the left bottom screen...however, when it gets to less than 5 minutes, it comes up with the message "countdown clock will hold at T-4 due to a failure"...then it just stops...I have no idea what to do after that...I exited the scenario, and tried the STS-126 scenario, and exactly the same happened...I cannot find any documentation to show what to do to ensure the scenarios run, but it looks like I have to input something....any ideas guys?...thanks in advance