I have a 2012 MacBook Pro (Retina) which I mostly use on my desk. The computer is "docked" via a Thunderbolt display, and additionally a third-party DVI display, which I have hooked up via an Apple Mini Display Port to DVI adapter (the active one, doing 2560x1440).

I use the MacBook during the day with the lid closed. So I work on the two external monitors. Via the Apple menu I put the Mac to sleep in the evening.

Sometimes, later in the evening, I like to take it downstairs and use it on my lap, so I unplug everything while the Mac is still asleep. I take the computer down and open it up.

Sometimes, when I open the lid up (not always) the internal screen does not come on. The back light illuminates, but there is no display.

I know the MacBook is alive because I can SSH into it.

Plugging the external monitors back in, in this state, has no effect. My only workaround at the moment is to wake it up and do my replugging while it's awake but I don't think I should need to do this.

So, what might be causing this how to resolve it?


5 Answers 5


In my experience, any Mac can be a little glitchy when waking from sleep out of "clamshell mode." Likely what is happening is that when you unplug the MagSafe and Thunderbolt connections from the MacBook Pro, it is waking up. Then the System Management Controller (SMC) gets confused because your Mac is trying to wake up but it's lid is closed (and the sensor is telling it) which usually means that you want your Mac to be asleep (because you don't have an external display or mouse/keyboard hooked up.) What often ends up happening is the Mac is "awake" but the display is "asleep."

Follow these procedures and you SHOULD get consistent behavior...

  1. wake up the MBPro by opening the lid
  2. unplug all your cables and make sure it was fully woke up
  3. then put it back to sleep by closing lid and/or carry to your desired destination.

Additionally, since you have setup remote login (via SSH) you could try telling the Mac to go to sleep via command line, wait 20 seconds, and then wake it up againe (open the lid/press a key on the keyboard.) This webpage describes the procedure:



  • Yeah, that worked for me. Now, I want to know how to make the internal display come back alive without having to unplug everything and put it to sleep again. Any clue @race_carr? Commented Jun 15, 2021 at 1:37

I would pay attention to two factors:

1) Do you have an external keyboard attached?

2) The power situation - how/when sleep happens is affected by this

3) If the lid is closed at the time you move the mac.

A couple of examples will help illustrate this:

Recently I found that my external keyboard was not waking up the closed lid mac as I thought it should. I found that this was because the power was unplugged and the 'lid closed' operation only worked with the power actually plugged in.

As another example I found that when my computer was asleep, in order to wake it up - without opening the lid! - the trick was to plug an external keyboard/mouse in and hit a key / move the mouse. This then took the mac out of sleep (though again that may depend on whether you have power plugged in or not).

  • Hm, interesting points. I have a keyboard/mouse attached to the thunderbolt display yes. So its basically a desktop replacement. This stops it going into standby when the lid is down. I manually put it to sleep when I'm done using it, then detach everything and then open it to wake it up. I'm working around this by opening it before detaching everything but I'd like a proper fix really :(
    – Caesium
    Commented Jul 20, 2012 at 21:35

I was having strange issues with my external monitor when waking my iMac from sleep. I reset my PRAM/NVRAM and it seems to have solved the issue (at least it hasn't come back in the week since I reset the PRAM/NVRAM).

Resetting PRAM and NVRAM instructions from http://support.apple.com/kb/HT1379

  1. Shut down the computer.
  2. Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
  3. Turn on the computer.
  4. Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
  5. Hold the keys down until the computer restarts and you hear the startup sound for the second time.
  6. Release the keys.

By any chance are you running gfxCardStatus? (I've had similar issues with my non-Retina MBP recently, and that's the only thing I can think of that I've installed in the past couple of weeks.)

If not, did you use Migration Assistant to setup this machine? Or did you set it up as a bare machine and manually reinstall apps and preferences?

I would look for extensions and other items that may not be compatible with the Retina-MBP hardware. Turn everything off and turn them on one-by-one, testing this issue each time.

  • I did try gfxCardStatus but no longer run it. I found that the Nvidia was required to run external displays anyway so keeping it around wasn't much use. It was a completely new install, no Migration Assistant.
    – Caesium
    Commented Jul 27, 2012 at 0:54

I have this problem constantly. It's hit-or miss. One way I found that works is I use Alfred and just tell it to sleep before I unplug. If the mac goes into normal sleep mode, unplugging will not cause issues. Actually I forgot -- "Apple" menu -> sleep should do the trick without Alfred.

Another possibility is to open the lid, wait for it to switch to dual monitor mode, unplug monitor, wait for it to switch to single monitor mode, close lid. This guarantees it will resume normally.

  • Yep, this workaround of open the lid, unplug, close lid, is what I'm having to do. It's not a proper fix but the closest I've got so far.
    – Caesium
    Commented Jul 27, 2012 at 0:55

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