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Have the clamshell mode requirements been relaxed?

I'm experiencing what I consider to be some odd behaviour regarding an external display hooked up to my MacBook:

With the external display being the only peripheral connected, the MacBook will enter clamshell mode when I close the lid.


It was my understanding (supported by documentation) that clamshell mode required output and input (a display and a keyboard and mouse; be they wired or bluetooth).
How can it make sense for a laptop to enter clamshell mode with only an external display connected?


When I close the lid with the external display connected:

  • the external display becomes the main display
  • all the windows that were open on the lid display pop across to the external
  • my desktop spread, littered with icons, appears on the external
  • the MacBook does not enter sleep


I don't have a bluetooth keyboard or mouse connected; I don't even have bluetooth on.

To the best of my knowledge I'm unaware of any settings that would affect this behaviour.


Does anyone else experience this same behaviour?
Have the clamshell mode entry requirements been relaxed in Mavericks (admittedly, I haven't used clamshell mode in previous versions)?

Is this a feature or a bug?

MacBook (13-inch Late 2009), OS X Mavericks (10.9.2)

Posted on Apr 2, 2014 3:18 AM

Reply
9 replies

Apr 2, 2014 4:02 PM in response to SeaPapp

Mike,
It's unclear how your reply helps answer my question. The Apple Support document you linked states:

Requirements for closed display mode:

  • Power adapter
  • External keyboard, mouse, or trackpad
  • External display

Assuming these requirements should be anded together, power and input and display (it makes no sense any other way), this continues to support the fact that my MacBook enters closed display mode without any input device, as aberrant behaviour.

Apr 2, 2014 4:45 PM in response to aka Lex

Taken directly from the article I linked to and posted above. Note the change beginning with Lion.

When you close the lid:

In OS X Lion and later, the external display will change to a blue screen, then will show your desktop.

In Mac OS X v10.6.8 and earlier, wake the computer up by clicking the mouse button or by pressing a key on your external keyboard.

Apr 2, 2014 5:37 PM in response to SeaPapp

Mike,
Thank you for responding so promptly.
I'm aware you quoted directly from the support article you linked, it's well within my ability to read that far down a web page.
However, those notes you share are under the heading: "Opening the internal display while in closed clamshell mode."
This indicates that the MacBook is already in clamshell mode and those notes inform me of what will happen when opening the lid from this state depending on which OS X I'm using. I'm not interested in this factoid. I'm raising the issue that my MacBook should not be entering clamshell mode in the first place without any input devices connected. Perhaps I should have made this more obvious in my original post.

Apr 2, 2014 6:47 PM in response to aka Lex

Reading comprehension is not your strong suit. Those notes are not under the heading "Opening the internal display while in closed clamshell mode."

Here, I've copied more for you. Opening the internal display is discussed much later in the article......MUCH later.

Requirements for closed display mode:


Power adapter

External keyboard, mouse, or trackpad

External display

Use these steps to enable closed clamshell (display closed) mode:


If you are using a wired keyboard and mouse:


Make sure the computer is plugged in to an outlet using the AC power adapter.

Connect a USB keyboard and mouse to your computer.

With the computer turned on connect the Mac notebook (using the appropriate Apple adapter if necessary) to the appropriate port on the external display or projector and turn the display or projector on.

After your computer's Desktop appears on the external display, close the computer's lid.

When you close the lid:

In OS X Lion and later, the external display will change to a blue screen, then will show your desktop.

In Mac OS X v10.6.8 and earlier, wake the computer up by clicking the mouse button or by pressing a key on your external keyboard.

You should now be able to use your Mac notebook as you normally would, with a USB keyboard and mouse.


If you are using a Bluetooth keyboard and mouse on a Bluetooth enabled Mac notebook:


Make sure the computer is plugged in to an outlet using the AC power adapter.

Verify that Bluetooth is turned on by using the Bluetooth pane of System Preferences or the Bluetooth menu icon.

Pair your Bluetooth keyboard or mouse with the computer. For step-by-step instructions, see this article for keyboard pairing or see this article for mouse pairing.

In System Preferences, be sure that the Allow Bluetooth devices to wake this computer option is selected.

With the computer turned on connect the Mac notebook (using the appropriate Apple adapter if necessary) to the appropriate port on the external display or projector and turn the display or projector on.

After your computer's Desktop appears on the external display, close the computer's lid.

When you close the lid:

In OS X Lion and later, the external display will change to a blue screen, then will show your desktop.

In Mac OS X v10.6.8 and earlier, wake the computer up by clicking the mouse button or by pressing a key on your external keyboard.

Apr 2, 2014 10:57 PM in response to frederic1943

Okay! So this is expected behaviour that other people experience?
This infers that the requirements listed in the support articles are inaccurate and that the only real requirement to initiate clamshell mode is the external display (I have verified that my MacBook enters clamshell with only the external display, without power adapter).

Now I'm really looking for someone to confirm that they, on whatever current series of MacBook/Pro, can reproduce this behaviour; to add weight to this being a feature (however odd), not a bug.

Apr 3, 2014 2:54 AM in response to aka Lex

Since Lion the Mac enters clamshell mode and the display lights up immediately. In Snow Leopard and before the computer would go to sleep first and had to be woken up by input from a keyboard or mouse. You are correct in that the procedure changed when Lion was released. Your MacBook is behavior is perfectly normal.

Have the clamshell mode requirements been relaxed?

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