Startup options on external monitor.

[skolhustick]

I have a Macbook Air Mid 2013 running Yosemite. My main display is broken due to an accident, but I have been successfully using an external display (thunderbolt to HDMI or thunderbolt to VGA, both works, no problem).

I wanted to make a Bootcamp installation and I have no problems with creating the USB and such.

The problem is, I can never get the startup options screen (after pressing 'option' on chime) to be displayed on the external monitor. My external monitors only pick up the display once I get into the user selection for MacOSX.

Using a few tricks, I have managed to get the monitor to display Recovery Mode(command + R), but never the Startup Disk selection menu. I sort of need Windows at the moment, and this is driving me nuts.

So I need to know, how to force the Mac to show the boot up / startup screen / startup disk selection / apple logo / on an external monitor?

Thank you.

 

[yjchua95]

I have a Macbook Air Mid 2013 running Yosemite. My main display is broken due to an accident, but I have been successfully using an external display (thunderbolt to HDMI or thunderbolt to VGA, both works, no problem).

I wanted to make a Bootcamp installation and I have no problems with creating the USB and such.

The problem is, I can never get the startup options screen (after pressing 'option' on chime) to be displayed on the external monitor. My external monitors only pick up the display once I get into the user selection for MacOSX.

Using a few tricks, I have managed to get the monitor to display Recovery Mode(command + R), but never the Startup Disk selection menu. I sort of need Windows at the moment, and this is driving me nuts.

So I need to know, how to force the Mac to show the boot up / startup screen / startup disk selection / apple logo / on an external monitor?

Thank you.

With the external monitor connected, press the power button and immediately slam the lid back down before the startup chime is heard.

Also, make sure that you're plugged in. Clamshell mode only works when MagSafe is connected.

 

[skolhustick]

Thank you for your suggestion. Well it works for entering the Recovery Mode. But not to the Startup Manager. I have tried with both VGA and HDMI displays. Any other suggestion?

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With the external monitor connected, press the power button and immediately slam the lid back down before the startup chime is heard.

Also, make sure that you're plugged in. Clamshell mode only works when MagSafe is connected.

Thank you for your suggestion. Well it works for entering the Recovery Mode. But not to the Startup Manager. I have tried with both VGA and HDMI displays. Any other suggestion?

 

[yjchua95]

Thank you for your suggestion. Well it works for entering the Recovery Mode. But not to the Startup Manager. I have tried with both VGA and HDMI displays. Any other suggestion?

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Thank you for your suggestion. Well it works for entering the Recovery Mode. But not to the Startup Manager. I have tried with both VGA and HDMI displays. Any other suggestion?

Weird. I got the startup manager running perfectly on my Dell S2240L via HDMI on my rMBP.

 

[ctapnep]

With the external monitor connected, press the power button and immediately slam the lid back down before the startup chime is heard.

Also, make sure that you're plugged in. Clamshell mode only works when MagSafe is connected.

Hi -
I know this thread is pretty old but I have a very similar question.
The problem - it's an iMac, so I can't shut the lid to get clamshell mode. Any way to do get the same behavior on iMac?

Thanks!

 

[F-Train]

Hi -
I know this thread is pretty old but I have a very similar question.
The problem - it's an iMac, so I can't shut the lid to get clamshell mode. Any way to do get the same behavior on iMac?

Thanks!

It’s unclear to me what you are trying to do. However, if you are trying to get a pre-boot screen, and you are using a wireless keyboard, there’s an issue about when the command registers. It’s a problem with my 2018 mini, which doesn’t even chime. There’s a simple solution. Use a wired keyboard and press the keys for the command right after, or indeed before, you press the power button. Works every single time.

 

[ctapnep]

It’s unclear to me what you are trying to do. However, if you are trying to get a pre-boot screen, and you are using a wireless keyboard, there’s an issue about when the command registers. It’s a problem with my 2018 mini, which doesn’t even chime. There’s a simple solution. Use a wired keyboard and press the keys for the command right after, or indeed before, you press the power button. Works every single time.

My iMac screen is broken. I'd like to use that iMac with external screen as my primary display. I have a wired keyboard and have no problem using whatever shortcuts, but system dialogs (like Recovery or boot selection) always default to the internal monitor. And I don't see any way to show them on the external screen.
in laptops one can shut the lid down which will trigger "clamshell" mode. But iMac has no such option

 

[adam4900]

My iMac screen is broken. I'd like to use that iMac with external screen as my primary display. I have a wired keyboard and have no problem using whatever shortcuts, but system dialogs (like Recovery or boot selection) always default to the internal monitor. And I don't see any way to show them on the external screen.
in laptops one can shut the lid down which will trigger "clamshell" mode. But iMac has no such option

Take screen off. Use razor blade. Use gap in centre of blade as depth guide. 1 cm max. Cut adhesive. Do not cut too close to camera at top. Pry open with credit cards. Open screen from top, (lean mac back -- this is dodgy way be careful) hold screen so doesn't fall, disconnect 2 plugs. U can find this on ifixit. Then u will get boot screen. Will be in a low-performance mode and fan will spin flat out. Mojave update said 2 hours to install in this config. Clean instal of high Sierra was only 30-40 mins. Imac 27 2013.
I just plugged back in and taped screen on with duct tape. If I need boot screen again I can get it. Thought of installing a switch on 1 lead of power plug and drilling a hole out back of case for a simple switch. Might even Dremel out a quick access SSD slot in back.

 

[ctapnep]

That's exactly what I did. But opening computer every time I wanna see "default screen" is a bit of a pain. For example, initial login screen is there. And I have to choose right account and log in blindly.
I bet there's a way to load DisableMonitor extension before login and set it to disable particular screen but I haven't figured out how to do it yet.