How to fix corrupt external hard drive (HDD) on Mac that stops you from mounting/unmounting/eject

Different things to try before you throw away your corrupt HDD. Mine wasn't mounting, ejecting, etc. I couldn't carry out first aid, erase, or anything else. BEFORE USING THESE TERMINAL CODES PLEASE WATCH VIDEO FIRST diskutil list = list of disks in use clear = clear terminal screen diskutil unmountDisk force (enter disk name from top code output) = force unmount sudo lsof|grep (enter disk name from top code output) = shows processes running from disk