Hmm, first of all, have you tried to use the Aero Glass Preview without AGTweaker ? If so, does it work without AGTweaker ? If not, please report the crash & debug log to bigmuscle (not me) If it works without AGTweaker, try to use the old dialog skipping method and disable the HideCMD workaround. If you cannot shutdown your computer that's because the provided password was incorrect, so explorer.exe could not be restarted under your own credentials and has limited capabilities. Note that the Start With Windows setting need administrator rights to be enabled, and the limited explorer cannot launch admin apps (UAC Prompt is not displayed and the app is launched as normal user) To regain full explorer.exe capabilities, please log off and log back to your windows account. ... I Hope that this has helped you to find the issue.