If your Mac includes the Apple T2 chip, then you need to modify Secure Boot settings in order to boot from Acronis Bootable Rescue Media and/or Acronis Survival Kit.
Secure Boot settings are available in Startup Security Utility:
- Turn on your Mac, then press and hold Command-R immediately after you see the Apple logo to start up from macOS Recovery.
- When you see the macOS Utilities window, choose Utilities > Startup Security Utility from the menu bar.
- When you're asked to authenticate, click Enter macOS Password, then choose an administrator account and enter its password.
- In Startup Security Utility, select the options Medium Security and Allow booting from external media.
See this Apple Support article for more information about Secure Boot settings.
The following Mac computers have the Apple T2 chip:
- iMac Pro
- MacBook Pro models from 2018
You can also use System Information to learn whether your Mac has this chip:
- Press and hold the Option key while choosing Apple menu > System Information.
- In the sidebar, select either Controller or iBridge, depending on the version of macOS in use.
- If you see "Apple T2 chip" on the right, your Mac has the Apple T2 chip.