http://updates-http.cdn-apple.com/2019/cert/061-39476-20191023-48f365f4-0015-4c41-9f44-39d3d2aca067/InstallOS.dmg
If your Mac is compatible with newer operating systems (like macOS Catalina, Big Sur, or Monterey), you may find that the Software Update pane no longer offers these upgrades. This is because Apple has removed older upgrade paths. You can still upgrade by manually downloading the installer for a newer macOS version, but be aware that not all Macs can run every newer OS. Mac Os Sierra 10.12.6 Dmg File Download
Click to pull the installer into your /Applications folder. How to Create a Bootable USB Installer http://updates-http
A DMG (Disk Image) file acts as a virtual physical disc. Having a standalone macOS Sierra DMG is highly beneficial for several distinct scenarios: Click to pull the installer into your /Applications folder
: The process takes 15–30 minutes. Terminal will display "Done" when finished. Installing macOS Sierra From the USB Drive Shut down the target Mac completely. Insert the bootable USB installer drive.
Your system will open the Software Update panel to pull the full installer. How to Create a Bootable USB Drive from the DMG
Where to get the installer safely