I was developing a Flex app and for the life of me I could not get it to use Flash Player 10 when it would compile. I downloaded the Flash Player 10 Projector content debugger and ran it. Nothing. I tried all sorts of editing flex config files, compiler arguments etc to no avail. Turns out you need to run the content debugger as ‘administrator’. (Right click ‘Run as Administrator). This fixed it up, no need to edit config files or add compiler arguments to my project. Hope this saves someone some headache as I had forgotten about this ‘feature’ on Windows 7.