Clicking Hard Disk Recovery, A Case Study

by admin

We recently received a drive from a client who had been told that in order to continue his hard disk recovery a head-swap would be necessary as the drive was clicking. This prognosis had been received from someone who in turn had almost certainly read online about the famous “click of death”. A sound which when heard always signifies that the drive heads have failed and will need to be replaced for a hard disk recovery to be possible.

It had come to us because the original data recovery company to whom he had had sent his drive  had offered an initially low price quote on the telephone but when they had physically received  the drive the price had suddenly sky-rocketed when the supposed need to replace the heads had been identified.

Does Any Clicking Sound Mean That Hard Disk Recovery Will be Needed?

The hard drive was indeed clicking as reported. This clicking is a result of the read/write head arm within the hard drive hitting a mechanical stop at power-down. A single click is therefore perfectly normal when a drive is switched off. What is typically happening in drives received for hard disk recovery where there is repetitive clicking is the drive starting-up and powering down repeatedly over a short space of time. While it is perfectly true to say that the majority of the times when this symptom occurs, the heads have indeed failed and their replacement is the next step towards achieving a hard disk recovery, there are a few vital caveats to note.


The clicking sound may not mean that hard disk recovery is needed

The clicking sound is made by the arm on which the heads are mounted hitting a mechanical stop (highlighted with the red arrow above)

Firstly there are many other possible causes of this behaviour, to have a good chance of a successful hard disk recovery it is essential to rule these out first. Prime amongst these is firmware corruption. Firmware is a set of instructions and configuration information stored on the hard drive and used by it in order to get itself up and running and to present itself as a recognisable storage area to your computer. This firmware is stored in part on the platters inside the hard drive and in part on the printed circuit board mounted on the outside of the hard drive’s chassis. If this firmware becomes corrupted it is common for the drive to spin-up, attempt to read the firmware, fail to do so satisfactorily and switch off, then immediately re-try by powering up again, this cycle can be repeated very quickly and so result in exactly the same clicking sound that would be produced by failed heads (and for much the same reason), both indicate the need for hard disk recovery, but by very different means. This was indeed the case with our client’s hard drive, had the first suggested hard disk recovery path been followed and the heads had been replaced, the problem would still have remained. There would be no point in replacing perfectly healthy heads and leaving the firmware un-repaired. Fortunately in this instance it was possible to replace the corrupted portion of the firmware on the client’s drive and a full hard disk recovery was achieved.

Another point worth bearing in mind is that even when the clicking is indeed caused by failed heads the question then becomes, what else has failed? One of the more common reasons for heads to fail resulting in the need for hard disk recovery is impact damaged caused by the heads briefly making contact with the platters. During the normal course of events the heads should never make physical contact with the data area of the platters, but sometimes this can happen (often through the drive taking a physical knock while in use), the result can be inoperable heads but crucially also platter damage. This platter damage will then pose a severe threat to the replacement set of heads. If the damage is bad enough then it can act much like a brick wall would in a head-on collision with the heads when the drive next spins-up. This type of platter damage almost invariably leads to a failed hard disk recovery.

Lastly there is also the issue of exactly what constitutes a “clicking” sound. One person’s click is another person’s scrape or beeping sound. At Tierra we routinely receive drives that have been reported as exhibiting the “click of death” only to find that the drive doesn’t spin-up at all and that instead there is clunking noise. The point is that the vocabulary is not precise enough to remove the need for a full analysis on any faulty hard drive to be approached with no pre-conceptions of what has failed.

As can be seen then, there are many possible causes of a hard drive clicking, correct diagnosis by an expert is therefore essential. For more information on how to proceed with a failed hard drive click here (no pun intended) . It is never wise to embark on a hard disk recovery attempt with pre-conceived ideas of what has failed, especially on such flimsy evidence as a “clicking” sound.

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