Last supported OS for many older MacPros, MacBook Pros, and iMacs.
If you get an error stating the installer is "damaged" or can't be verified, the issue is often expired certificates. The best way to fix this is to set your system date to 2018 or 2019 using date command in Terminal before running the installer.
Keep holding the key until the Startup Manager screen appears showing your available boot drives. macos high sierra 10136 dmg install
Turn on the Mac and immediately press and hold the Option (Alt) ≠ key. Select the "Install macOS High Sierra" USB drive from the menu.
At least 14.3GB of available space for the upgrade. Compatible Models: MacBook: Late 2009 or newer. MacBook Air/Pro: Mid 2010 or newer. Mac mini: Mid 2010 or newer. iMac: Late 2009 or newer. Mac Pro: Mid 2010 or newer. Where to Download macOS High Sierra 10.13.6 DMG Last supported OS for many older MacPros, MacBook
Follow the link to download the app or DMG.
Ensure your formatted USB drive is connected and named HighSierraUSB . Open . Keep holding the key until the Startup Manager
From the macOS Utilities window, select and click Continue .