A few days ago I upgraded my MacBook Air from 10.8.4 to 10.9 developer preview 4 in order to start compatibility testing against the applications and processes we use through our office in preparation for when Macs ship with Mavericks in the Fall. Just came back from lunch to the message below. I haven't made any significant changes over the past two days and have actually only lightly been using the Mac today since I've been running around the office. I've seen similar alerts in the past (10.6, 10.7, etc) for specific applications (Safari would like to access.., etc) but never for System Events. Any ideas as to what could have triggered this? Only reason I didn't post in an OS specific section was because I've seen similar alerts in the older systems, honestly making me unsure as to if this is a 10.9 specific issue.