A “head crash” is a term that describes what happens when the read/write heads of a hard drive touch the spinning platter causing damage to the magnetic coating that contains the data.
A hard drive is somewhat like a record player in that there are spinning platters (records) that are read by read/write heads on an actuator arm (the tone arm and needle). Instead of the r/w heads actually touching the platter though, it hovers just above it reading the data magnetically. Sometimes it’s a small bump or jarring of the disk, sometimes it’s a small piece of dirt or other particulate on the disk surface. Whatever the cause, if the read/write heads touch and chip or scratch the magnetic coating of the spinning platter(s), that is a head crash!
A head crash has to be handled carefully as once it happens and some coating has been scratched off the platter(s), the problem become worse very quickly. You have to catch it quick before all of your data is literally scratched off. A common disk speed is 7200 RPM – that’s almost 75 mph! A head crash occurring at that speed can be catastrophic.
Be smart. If you hear clicking, clunking, grinding or any other odd noises you could possibly have a head crash. We suggest you pack it up and send it to a company that you know will give you the best chance of recovery.