Below is a detailed, step-by-step guide to help you find and install this classic operating system safely, including how to fix the most common errors.
After completing these steps, you will find a fully-functional "Install macOS Sierra.app" in your Applications folder. download macos sierra 1012 dmg file install
The installation process can take anywhere from 20 minutes to an hour depending on your hard drive speed (SSDs are significantly faster than traditional HDDs). Your Mac will restart automatically during this process. Do not unplug the USB drive or close the laptop lid until the setup assistant screen appears. Troubleshooting Common Installation Errors Below is a detailed, step-by-step guide to help
Apple hosts the macOS Sierra installer on their servers. You can download the installer image directly through your web browser. Open your web browser. Your Mac will restart automatically during this process
Before installing, ensure your Mac supports macOS Sierra 10.12: (Late 2009 or later) MacBook Pro (Mid 2010 or later) MacBook Air (Late 2010 or later) iMac (Late 2009 or later) Mac Mini (Mid 2010 or later)
But there is one complication: Apple has officially removed Sierra from the Mac App Store. This means you can't just "re-download" it from your account's "Purchased" tab, as is still possible for many other versions. However, that does not mean all hope is lost. This guide will walk you through every legitimate method for finding, downloading, and creating a bootable installer for macOS Sierra.
Disconnect your Mac from the internet. Open Terminal during installation and change the system date back to 2017 using the command date 0101010117 . "The installer payload failed signature verification"