Starting with macOS 10.13 ‘High Sierra’, Apple completely removed all of this functionality from the Mac operating system, making it impossible to perform disk permissions validations and repairs.

Apple had previously removed the disk permissions functionality from the Disk Utility application starting with OS X 10.11 ‘El Capitan’. However, we were still able to utilize some remaining functionality to perform that operation through Techtool Pro for OS X 10.11 and macOS 10.12 ‘Sierra’.