Issue

Trying to install a fresh copy of macOS High Sierra on a MacBook Air using a bootable USB key. The installation fails to proceed with the following error:

This copy of the Install macOS High Sierra application is damaged, and can’t be used to install macOS.

Resolution

The issue was caused by an old High Sierra installation image, most likely due to an expired certificate. To resolve the issue I had to re-download a new installation image from Apple and re-create the bootable USB key.

April 2021
MacBook Air (2011)
macOS High Sierra