If your installer is an older version of High Sierra, you can jump straight to the final build by downloading the directly from Apple’s website. This ensures all security patches are up to date.
: If your Mac is compatible, searching for "High Sierra" in the App Store may allow you to click Get or Download . The file will be saved as "Install macOS High Sierra.app" in your Applications folder. download+macos+high+sierra+10136+dmg+mac+install