Is the reverse even true? I.e. can a process elevate itself mid-run? I was under the impression that it can't; that, at best, you can start a new process with the appropriate privileges.
There's some discussions out there on how to run an app as user from a higher elevation... one using the Task Scheduler ( http://www.codeproject.com/KB/vista-...aElevator.aspx
), one doing crazy things by getting the desktop (which it presumes to be non-elevated) and spawning a new process using that desktop's security tokens ( http://blogs.msdn.com/b/aaron_margos...vated-app.aspx
) and another that looks entirely like hieroglyphics after gazing at it for 2 minutes ( http://brandonlive.com/2008/04/27/ge...ou-part-2-how/
But they're all about starting new processes - in which case, the UAC plugin should work quite well within the NSIS context and would be more flexible.