Two other unrelated items of interest I spotted while scouring Apple's latest support articles:

: "Apple has determined that a small number of MacBook Pro (15-inch, Mid 2010) computers may intermittently stop displaying video on the built-in display or on an external display connected to the MacBook Pro." Apple is working on a solution.

Apple's latest article on offers a new tip I had not seen before: Reset the Lockdown folder. Read the article for full details. Briefly, go to /var/db/lockdown and delete all the files in the folder (not the folder itself).