enabling Assistive Devices in 10.9
In Mavericks, Accessibility for Assistive Devices is no longer a global setting, but has to be turned on explicitly on an app-by-app basis. That setting has now moved to the Security & Privacy pane in System Preferences.
If you’re running System Events in AppleScript, Automator or using apps like BetterTouchTool that require Assistive Devices, you’re likely to come up against an error message. For example, a simple script like this:
tell application “System Events”
tell application process “Safari”
will return an error message like this: