I've been having an issue with my 13-inch MacBook Pro with Retina Display (Late 2013). I'd be interested to know if anyone else is having a similar issue. Issue: OS X 10.9 not prompting from password upon opening the lid after sleep. It only happens about 1 in 5 times that I open the lid. About 4 out of 5 times it does prompt for a password. Steps to replicate: Close lid. Let MacBook Pro sleep. Open lid. No password prompt. Failed attempts to fix: Formatted HD using external Mavericks boot USB. Reinstalled fresh copy of 10.9. Restored from Time Machine. Toggling all possible "Require password X seconds after sleep" setting and toggling feature on and off completely.