The term 'High Sierra Runner' refers to a MAC computer software program developed by Apple Inc. It is designed to help users manage their files and folders, as well as optimize their system performance. The acronym for this program is MAC, which stands for Media Access Control. High Sierra Runner is compatible with macOS High Sierra and later versions of the operating system. It is a powerful tool that helps users organize their data, improve system performance, and protect their data from malicious attacks.