I have an external LG monitor connected through a display port cable to a LaCie big5 and then by thunderbolt to my rMBP.. Things were working just fine before 10.9.3. There sometimes was a number of screen on/off flashes during boot up or wake, but otherwise seamless. Prior to 10.9.3, on wake, is seemed that some video (dim desktop) was fed to the external monitor whenever the login screen was displayed. In 10.9.3, it seems like video is not being sent to the external monitor until I enter the password. So if I'm not quick enough (~15 seconds), the external display just goes back to sleep and there doesn't seem to be anyway to bring it back except a rMBP restart. Turning the display on and off manually does not seem to trigger the OS to recognize that the display connected. Also, since the monitor is not quite woken up when the rMBP releases the lock, the external monitor windows get resized. Any other see this minor issue/quirk? Looks like the broke a couple things with the latest fixes. In 10.9.2 and earlier (on two different rMBPs) I had sleep/insomnia issues, where periodically it seemed like the rMBP would wake up the monitor (did something on the TB port I suspect). I learned to just turn off the monitor after putting the rMBP to sleep, and turning it back on before waking the rMBP. The daisy chain through the Big5 resolved that issue nicely, however. Update: I notice the Apple support forums full of similar issues.