With your bootable USB ready, follow these steps to install: to the target Mac. Restart the Mac while holding the Option (Alt) key.
This often happens due to an expired security certificate. To fix this, disconnect from the internet, open Terminal in the installer environment, and set the system date back to 2017 using the command date 0101010117 . download macos sierra 1012 dmg file install
MacOS Sierra 10.12 remains a vital operating system for users running older Mac hardware or those needing to maintain compatibility with legacy software. Whether you are performing a clean install, reviving an older MacBook, or setting up a virtual machine, having a reliable DMG file is the first step. With your bootable USB ready, follow these steps
This does install the OS; it extracts the "Install macOS Sierra" application into your Applications folder. Creating a Bootable USB Installer To fix this, disconnect from the internet, open