Double-click the downloaded file to mount it. Open the mounted volume and double-click InstallMacOSX.pkg . Follow the on-screen prompts in the guided installer.
Before you attempt to download or install macOS Sierra, you must ensure your Mac is compatible. If your Mac does not meet the minimum requirements, the installer will not run.
Note: macOS 10.12 Sierra is an older macOS release. The methods below describe official routes and safe steps to obtain the full installer for reinstalling or creating a bootable USB. Do not use unofficial or pirated copies.
: Apple officially ended security updates for macOS Sierra on November 30, 2019 Security Risks download macos 1012 sierra full
sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ macOS\ Sierra.app
Disconnect your Mac from the internet. Open Terminal before running the installer and change your system clock to a date close to the release of Sierra (e.g., September 2016). Use the command: date 0920000016 . Download Stalls or Fails
Open (Applications > Utilities), select your flash drive, and click Erase . Double-click the downloaded file to mount it
It introduced tools to automatically move seldom-used files to iCloud Drive
The downloaded file is a disk image ( .dmg ) containing an installer package, not the actual application needed to create bootable media. Follow these steps to extract the full installer:
This process extracts the software and places a file named directly into your Applications folder. System Requirements for macOS Sierra Before you attempt to download or install macOS
At least 2 GB of RAM (4 GB or more is strongly recommended).
Replace MyVolume with your USB drive’s exact name.