Logical problems with External Hard drives:
- File system failure, for example external hard drive file system turned to RAW, which can be caused by suddenly unplugging the drive. When trying to open a drive, system asks you to format it – don’t.
- Accidentally formatting the external hard drive. It is important to never write anything onto an external hard drive you need to recover data from.
- Deleting wrong files by mistake. It is important to stop using the drive immediately once you discover a data loss.
Physical Hard drive Problems:
A hard drive can fail in many ways, caused by various reasons. Most common failure modes are :
- Logic board (controller) failures.
- Broken power/data connectors (requires fine soldering).
- Spindle/arm driver chip failure (requires replacement of either a logic board, or a chip; additional repairs may be needed depending on the true cause of the problem).
- Head block pre-amplification failure (platter box must be opened).
- Moving parts failures.Firmware corruption (requires special software and sometimes special connection arrangement).
- Head crash.
- Spindle bearing seizure or spindle motor failure.
The hard drive is most likely physically damaged, if any of the following symptoms is evident :
- There is a problem apparent on the exterior of the drive, like visible damage to the chips and/or connectors.
- The drive is not listed in Widows Disk Management, Windows Device Manager, and in the system BIOS.
- The drive remains silent (no spin-up sound, no movement/vibration felt) when powered up.
- The drive emits loud clicking noise when accessed. Typical pattern would be repetition of click-pause-click-pause-click, followed by the sound of the drive stopping and then spinning up again. Windows typically locks up or feels “sluggish” for the entire duration of the sequence.
Note: It’s very important to stop using the drive immediately, once you discover a data loss.