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Mac computers equipped with a T2 chip have an added feature called secure boot. It prevents unsigned operating systems from running on your Mac. Secure boot helps protect against bootkits, or malware that infects the master boot record (MBR) on your computer. While there should be no need to change this setting, if you plan on installing an older operating system such as macOS Sierra and earlier or run operating systems that are unsigned such as some distributions of Linux, you may need to disable secure boot to be able to run these needed operating systems. This wikiHow will show you how to disable secure boot on Mac so you can boot a legacy version of Windows or macOS or an operating system that does not support secure boot.[1] X Research source Go to source
Steps
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1Press ⌘ Command+R on the keyboard. While doing so, start up your computer. You will see the macOS Utilities window.
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2Open Startup Security Utility. From the menu bar, choose "Utilities" > "Startup Security Utility". You will need to provide authentication via a Mac administrator username and password to proceed.
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3Choose "No security". This will disable secure boot.
- If you do not want to disable secure boot entirely, you can choose "Medium security" which allows for pre-signed operating systems to run. The default "Full security" option requires signatures from Apple to run. This will require an internet connection at installation time.
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4Restart your Mac. From the Apple menu, choose "Restart". You should now be able to run legacy versions of operating systems to run.
- If you have trouble, then make sure that there is not a firmware password and that you are an administrator on your Mac.
Community Q&A
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QuestionHow do I check if it is enabled or disabled via Terminal Command?AasimTop AnswererUnfortunately, you cannot check the status of Secure Boot with Terminal or Command Prompt. Because Secure Boot is a firmware setting that you have to change in the Mac recovery environment, you need to boot into the recovery environment to view that setting.
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QuestionWhy can't I log in after turning off secure boot?AasimTop AnswererOn newer operating systems, including Windows 10, secure boot is mandatory, and the operating system will not start if it is disabled.
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Warnings
- Under normal circumstances, you should not turn off secure boot. This makes your computer more vulnerable to rootkits or bootkits.