I have a 2012 rMBP and using two external LED Cinema displays. When I use both external displays in clamshell mode, I put the computer to sleep and disconnect the external monitors. When I wake from sleep with just the laptop screen, I only see a black screen. I see a slight flash of the wallpaper and login window, but then it's just black. I can type in my password and then the laptop screen comes on and back to normal. Has anyone seen this? BTW, it works just fine when I'm only using one external display and I have no issues going from laptop screen to dual external displays, only from dual external displays to the laptop screen. I've already done a NVRAM and SMC reset. I've deleted the /Library/Preferences/com.apple.loginwindow.plist file, anything else I should be looking for? Thanks.