1. Download "Global Hotkey" 2. Create a folder "Global Hotkey" and copy contents of downloaded DMG to that. 3. In a terminal do: cd "/Applications/Global Hotkey" ln -s /System/Library/Frameworks/ScreenSaver.framework/Versions/A/Resources/ScreenSaverEngine.app "command f10" 4. Make sure Screensaver is set to prompt for password (you may need to relog for this to take effect) 5. Preferences -> Accounts -> -> Login Items : Add "Global Hotkey.app" 6. Launch the app as well