YOU MUST AUTHENTICATE TO UNLOCK THE SCREEN
http://discussions.apple.com/thread.jspa?threadID=1203732
Occasionally (once or twice a week) when I return to my MacBook, instead of the usual screen saver, followed by the usual login window with my username filled in... just waiting for my password... it is displaying the "Flurry" screen saver (which I have never used), followed by a strange login box with the text:
"YOU MUST AUTHENTICATE TO UNLOCK THE SCREEN. TYPE IN AN ADMINISTRATOR'S NAME AND PASSWORD TO MAKE CHANGES TO MAC OS X."
No mater what one types in there fields, it is impossible to login. The only solution is to power off and login after the reboot. This is REALLY frustrating.
I have a suspicion that this may be some sort of an attack, but there is absolutely no information on the web about it, except the one post mentioned above (which I guess never satisfactorily solved magnettarpit's problem either.
Thanks in advance for any assistance.
MacBook Pro, Mac OS X (10.4.11)