Visit the official Apple Support page to download High Sierra.
Optional: Select to erase your internal drive for a clean install. Select Install macOS from the main utilities menu. Click Continue and accept the software license agreement. Choose your target internal hard drive. Click Install and let the automated process finish. Troubleshooting Installation Errors Solutions for common issues encountered during setup. "This copy of the Install macOS application is damaged" Open Terminal in Recovery mode. download+macos+high+sierra+10136+dmg+mac+install
I can then provide tailored troubleshooting steps for your machine. Share public link Visit the official Apple Support page to download