Double-click and follow the on-screen prompts.
Release the key when you see the Startup Manager screen showing available boot drives.
Open the mounted disk and double-click the InstallMacOSX.pkg file.
Apple provides older installers via their support website. Depending on your current operating system, this might download directly as a .dmg or as an .pkg installer that places the "Install macOS Sierra" app in your Applications folder. Method 1: The Official Apple Support Link download macos sierra 1012 dmg file install
The terminal erases the USB, copies the hidden BaseSystem.dmg , and makes the drive bootable.
How to Download and Install macOS Sierra 10.12 DMG File Apple officially released macOS Sierra 10.12 in 2016. It introduced Siri to the Mac, optimized storage solutions, and offered seamless integration with the Apple Watch. If you need to revive an older Mac, set up a virtual machine, or create a bootable installer, you will need a clean macOS Sierra 10.12 DMG file.
Downloading and installing macOS Sierra (10.12) is straightforward if you use the official Apple-provided disk image. This version is available directly from Apple's support pages because it is no longer listed on the standard App Store search. 1. Download the macOS Sierra DMG To get the official file, follow these steps: Double-click and follow the on-screen prompts
Press to confirm you authorize the volume to be erased, then wait for the terminal to print a line indicating success ( Update complete. Done. ). Boot From the USB Drive Shut down the target Mac completely.
Launch the on your Mac. Avoid third-party browsers like Chrome or Firefox, as Apple's CDN payload protocols integrate natively with Safari's downloading architecture.
Press , type your system administrator password when prompted, and press Enter again. Apple provides older installers via their support website
If you hit a roadblock during any part of this setup process, tell me: What are you seeing? What is the exact model and year of your Mac?
How to Download macOS Sierra 10.12 DMG and Install It: A Complete Guide