Will you continue to use medium

Information about the startup security utility

Use the startup security utility to ensure that your Mac always starts from the startup disk you specify and from a legitimate, trusted operating system.

Open the startup security utility

  1. Turn on your Mac and hold down Command (⌘) -R immediately after the Apple logo appears. The Mac will start from macOS recovery.
  2. When prompted to select a user whose password you know, select the user, click Next, and enter their administrator password.
  3. When the macOS Utilities window appears, choose Utilities> Startup Security Utility from the menu bar.
  4. When prompted for authentication, click "Enter macOS password". Then select an administrator account and enter the associated password.

Set firmware password

With a firmware password, you can prevent others who do not know the password from booting from a volume other than the startup volume you specify. To set a firmware password in the startup security utility, click Enable Firmware Password, then follow the on-screen instructions. More information on firmware passwords

You can also change your external startup setting to prevent even people who know the firmware password from starting from external media.

Change the Safe Boot settings

You can use these settings to ensure that your Mac always starts on a legitimate, trusted operating system.

Full security

"Full Security" is the default setting and provides the highest level of security. This is a level of security that was previously only available on iOS devices.

During the startup process, your Mac will check the integrity of the Operating System (OS) on your startup disk to make sure it is legal. If the operating system is unknown or cannot be verified as legitimate, the Mac will connect to Apple to load the updated health information needed to verify the operating system. This information applies to your Mac only, and it ensures that your Mac is starting up on an operating system that Apple trusts.

If FileVault is enabled when your Mac tries to load the updated health information, you will be prompted for the password to unlock the volume. Enter your administrator password, then click "Unprotect" to complete the download.

If the operating system fails the check:

  • macOS: A warning will appear informing you that a software update is required in order to use this startup disk. Click Update to open the macOS installer, which you can use to reinstall macOS on the startup disk. Or click Startup Disk and choose a different startup disk that your Mac will also check.
  • Windows: A warning will appear informing you that you must use Boot Camp Assistant to install Windows.

If your Mac can't connect to the internet, it will display a warning that an internet connection is required.

  • Check the internet connection, for example by selecting an active network from the Wi-Fi status menu in the menu bar. Then click on "Try Again".
  • Or click Startup Disk and choose a different startup disk.
  • Or use the startup security utility to lower the security level.

Medium security

If Medium Security is turned on, your Mac will check the operating system on your startup disk during startup. This only ensures that it has been properly signed by Apple (macOS) or Microsoft (Windows). It does not require an Internet connection or updated health information from Apple; That is, it won't prevent your Mac from using an operating system that Apple no longer trusts.

If the operating system fails the check:

  • macOS: A warning will appear informing you that a software update is required in order to use this startup disk. Click Update to open the macOS installer, which you can use to reinstall macOS on the startup disk. An internet connection is required for this. Or click Startup Disk and choose a different startup disk that your Mac will also check.
  • Windows: A warning will appear informing you that you must use Boot Camp Assistant to install Windows.

Without security

The "Unsecured" setting does not enforce any of the above security requirements for your startup disk.

Change the settings for "External start"

Use this feature to determine whether your Mac can be started from an external hard drive, flash drive, or other external media. The default and most secure setting is "Prohibit starting from external media". When this setting is selected, your Mac cannot be made to boot from external media. If you try, your Mac will say that your security settings do not allow this Mac to use an external startup disk.

To allow your Mac to use an external startup disk:

  1. Open the startup security utility.
  2. Select "Allow starting from external media".
    Your Mac does not support booting from network volumes, whether you allow booting from external media or not.
  3. If you'd like to choose an external startup disk before restarting your Mac, exit the Security Startup utility, then choose Startup Disk from the Apple menu ().
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