Scratching Sound Emanating from the Hard Disk

By: James Walsh

Suspecting hardware or some other mechanical problem, I checked the cables, but they were firmly attached at the back of the pc. Next, I removed the case cover off the computer to check if the cables inside the system, like the power and the hard drive cable were secure in their place. They were also secure in their location. Finally, I felt the top of the CPU which was warm and not hot.

Apprehensively, I restarted the computer. The screen remained blank and this time, I heard peculiar noises emanating from the system. The noise seemed like a scrapping sound. I knew that clicking and scraping or grinding noises indicated that the pc has lived its life and was on its way out. A scraping sound from the computer portends ominous tidings and I immediately switched of my system to prevent further damage. I knew that such a sound indicated the scratching of the read/ write head on the magnetic platters. Switching off the system was necessary. Otherwise, the scrapping of the magnetic matter would further damage the data.

The Story of the Scratching Noise

To understand why the scraping noise actually occurs, we need to go on a virtual tour of the hard disk. The HDD among other components also contains magnetic platters that have individual read/ write head hovering above them. The read/ write head is made of a thin film material and it flies in air that lies trapped over the magnetic platter. However, the head contains materials that are hard enough to scratch through the protective layer of the platters and damage the underlying surface.

The platters in the hard disk are coated with a lubricating material. Under this Teflon-like material lies a layer of sputtered carbon and below it is the thin magnetic layer on which resides the precious data. The magnetic platters spin at an rpm of 7,200 and the speed at the edge of the platters is around 120 km/hr. When the disks are revolving at such great speeds, any minute contact of the read/ write head with the platters is enough to cause damage. The pc user is alerted of such contact by the scraping or scratching noises that emanate from the system.

Such crashes wipe a small portion of data, off the magnetic platters, but the rest of it can be saved. However, data-salvaging work should not be self-attempted. The hard disk should be handed over to the data recovery experts. Data recovery software should also not be used in such circumstances.

How to Deal with Scratching Noises that Emanate from Your Computer

One redeeming factor of the whole issue is that hard disks crash with prior warning in 6 out of 10 cases. You should be alert enough to recognise these warning signals. Cautionary signals occur in the form of frequent disk error messages or peculiar noises from the system that may sound like a clicking, whirring, grinding or scraping sound. Unpredicted failures are sudden, and they occur due to damage by static electricity or wrong handling of the system. Respond to this critical situation by immediately creating a backup for all your important files. This is the only precautionary move you can take, before switching off your system.

Never try to power on and off the pc or use over the counter diagnostic tools for data recovery. If you are already booted up, shut down the computer immediately. Keeping the computer powered on would result in extensive data damage.

The head crash usually occurs when a speck of dust gets lodged on the magnetic platter. The distance between the read/ write head and the magnetic platter is 1-2 micro inches (that is one millionth of an inch.) A speck of dust measures around 4-8 micro inches while human hair is about 10 micro inches. If such particles get lodged on the hard disk platters, head crashes are bound to occur. Even moving the computer while it is powered on might lead to such an occurrence. So, whenever you hear a scratching sound from your computer; do what all pc users do -- simply shut down the system and place a call to data recovery service providers, if you have lost valuable data.

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James Walsh is a freelance writer and copy editor. If you are concerned about data loss and would like more information on Data Recovery see

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