Whether footage can be saved depends on whether the failure is logical or physical.

• Logical damage: a corrupted partition table, file system or recording index leaves the platters readable, so specialist recovery software or a recovery service can often extract the recordings. Stop writing to the drive immediately to avoid overwriting the data.
• Physical damage: clicking or grinding noises, or a drive that draws power without being recognised, usually means head or platter damage. Further power-ups cause more scoring, so send it to a laboratory with a cleanroom.
• Arrays and multi-bay units: after a single-drive failure on a RAID or multi-bay recorder, do not rebuild the array casually. A wrong initialisation destroys the remaining data.

Prevention matters more: enable SMART monitoring and bad-block alerts, export important footage to backup or cloud storage regularly, and use dual-drive redundancy or a local-plus-cloud scheme on critical sites.