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I am wondering if it is possible to record the screen of a Mac or take screenshots of it during its initial setup phase.

I hope to accomplish this with the hardware and not use an external camera or video capture device.

Can a Mac record it’s own boot process?

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4 Answers 4

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Not without additional hardware, because the OS & therefore the frameworks to support it are by definition not yet running.

You could video it with your phone.

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    Here's a RubeGoldberg method I used last time I needed to do this. Connected the Mac in question video output to an Avocet KVM, then connected to the KVM from another computer over the network. Not that most people have an Avocet lying around. Dec 3, 2023 at 17:37
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    Just use a HDMI capture card/USB box. Those are very commonly used by streamers.
    – user71659
    Dec 4, 2023 at 6:24
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    The phone is probably the easiest...
    – Nelson
    Dec 5, 2023 at 1:48
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Exactly which Mac?

For an all-in-one like a Classic, then no. The best you can do is a telecine where a camera is carefully centered and focused on the display, and has the frequency synchronised to stop rolling-shutter effects.

For any Mac with a monitor output port, then it should be possible to use a hardware capture device, which passes the image through to a monitor. Essentially these "vampire" the image as it goes to the external monitor, saving video or stills to a separate device.

If you're using an AWS mac.metal image, then it can be done to get a still screenshot of them booting, but it's more fiddly and the machine won't wait for you.

Your final option is to search your favourite search engine for an image someone else has already snagged, like this:

Photo of the Mac Startup Drive on boot
From Change the Mac Startup Drive on Boot

by using search terms "mac II boot screen" on Google.

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What about running macOS from a VM? That would allow you to capture the startup sequence video using the host machine's facilities.

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    @Criggie No. You can run up to 2 virtualized copies of macOS on Mac hardware for development or personal use. See paragraph 2(b)(iii) of the EULA. This is officially supported by e.g. VMWare Fusion and Parallels Desktop.
    – user71659
    Dec 4, 2023 at 6:20
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    In my experience, the boot sequence in a VM is very different from the boot sequence on actual hardware. The two don't converge until you reach the login screen.
    – Mark
    Dec 4, 2023 at 23:10
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    Honestly, I'm not sure if I'm more impressed that people 1) read the EULA, 2) actually comply to its unenforceable demands :D
    – Alexander
    Dec 5, 2023 at 0:44
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    @Criggie legalese aside, it works. It works on Windows machines, too.
    – Gábor
    Dec 5, 2023 at 17:17
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    @Criggie that was changed with 10.7 Lion. Prior to Lion, there was a separate server version of OS X that Apple sold which allowed virtualization. With Lion, they got rid of OS X Server and changed the OS X license to allow virtualizing the standard version. Dec 5, 2023 at 22:11
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This isn't an answer to your question really, but if you're trying to record the verbose output of boot sequence so you actually have time to read the text, then this command will show you almost all of that text.

sudo log show --predicate "processID == 0" --start $(date "+%Y-%m-%d") --debug

it does not include the output of the GRUB bootloader right at the start though, just everything from the start of the kernel loading

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