Reinstall macOS
How I can reinstall macOS high Sierra by internet
Question marked as
Best reply
Start up from macOS Recovery
To start up from macOS Recovery, turn on your Mac and immediately press and hold one of the following combinations on your keyboard. Command-R is generally recommended, especially if you never installed macOS Sierra 10.12.4 or later… https://support.apple.com/en-us/HT204904#notupdated
Command (⌘)-R
Install the latest macOS that was installed on your Mac.
Option-⌘-R
Upgrade to the latest macOS compatible with your Mac.
Shift-Option-⌘-R
Install the macOS that came with your Mac, or the closest version still available.
Or...
Try installing this in Safe Mode, but not using Firefox...
https://itunes.apple.com/us/app/macos-mojave/id1398502828?mt=12
Safe Boot, (holding Shift key down at startup).