Booting from external media

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benjamism Author

Level 1

8 points

Booting from external media

Hi, I am trying to boot from external media but have no option for it.

Here are my computer's spec

MacBook Pro (Retina, 13-inch, Early 2015)

Processor 2.7 GHz Dual-Core Intel Core i5

Memory 8 GB 1867 MHz DDR3

Startup Disk Macintosh HD

Graphics Intel Iris Graphics 6100 1536 MB

I follow the step below,

Restart your Mac and press and hold Command + R as soon as you see the Apple logo.
You should now see the macOS Utilities window. Select Utilities > Startup Security Utility.
Now enter the macOS password, select an administrator account and enter its password.
In the External Boot section check the Allow booting from external media option.

I try many times in Startup Security Utility, but I have no idea why I do not see Secure Boot/ External Boot section. It does not even prompt me to select an administrator account or to enter its password.

Is my device weird? or how should I do to see that section?

[Re-Titled by Moderator]

Posted on Jan 9, 2021 11:50 PM

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Answer 1

Top-ranking reply

Encryptor5000

Level 5

7,662 points

Jan 10, 2021 9:08 AM in response to benjamism

Hi benjamism,

Thanks for the detailed description.

The Secure Boot and External Media options are only available for Macs that have the T2 Security Chip. Your Mac does not have this chip, and will instead use the below security policy:

Secure Boot: None (no support)

External Media: Allow booting from all external media

If you want to prevent others from starting macOS Recovery or using a different startup disk, set a firmware password on your Mac. Be warned, though, that if you forget it, you'll need to bring proof of purchase to Apple in order for them to remove the password.

Also, consider enabling FileVault on your Mac so that your password is required to access your data, no matter what startup disk you use.

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Answer 2

benjamism Author

Level 1

8 points

Jan 11, 2021 3:24 PM in response to Encryptor5000

Thank you for your answer.

Btw, how can I boot from external drive(USB)?

After I get into Recovery Mode, and I choose different drive(USB) other than internal to boot.

However, it always reboot from internal thing.

Can you please help me how to boot from external drive?

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Answer 3

Jan 12, 2021 5:09 PM in response to benjamism

You can not just provide all the files on the USB-stick and expect it to be bootable.

Making a USB-stick Installer that is bootable requires a complex procedure described in the article below.

How to create a bootable installer for macOS - Apple Support

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Answer 4

Jan 12, 2021 6:03 PM in response to benjamism

You could try it on your MacBook Air to test.

If you're looking to create a bootable installer for macOS, follow the instructions given by Grant Bennet-Alder first.

If you're looking to flash an operating system onto the USB drive itself, ensure that the OS installer succeeded in installing all of the relevant files onto the USB drive to make it bootable.

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