Step 2: Prepare Your Target Hard Drive (Optional for Clean Install)
Note: If you use a modern Mac running macOS Ventura, Sonoma, or Sequoia, your computer will download the DMG file but will prevent you from opening the installer application natively because the app certificates have expired on modern architectures. Step 2: Extract the Installer Application
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? download macos sierra 1012 dmg file install
Release the key when the startup manager screen reveals available storage drives.
sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ macOS\ Sierra.app Use code with caution. Copied to clipboard Type your admin password and press to confirm. 4. Install macOS Sierra Restart your Mac while holding the Option (⌥) Select the USB drive labeled Install macOS Sierra Disk Utility Step 2: Prepare Your Target Hard Drive (Optional
You must temporarily trick your Mac's internal clock into believing it is still the year 2016 or 2017 before launching the installer.
This highly common issue stems from expired security certificates embedded within older Apple installer files. You can bypass this check by temporarily reverting your Mac's system clock to a date closer to 2016 or 2017. Release the key when the startup manager screen
Copy and paste the following precise command string exactly into the terminal line window to call Apple's built-in createinstallmedia tool: