"The click of death" is an expression that refers to the sound made by a failing disk drive in a computer or storage device. The term has been relatively common since the late 1990s. The most frequent use of the phrase seems to have originated from the problems encountered with removable storage systems.
As of early 2011, the majority of electronic data was maintained on rotating disc computer storage media. In the case of hard drives and removable storage devices, there is a reading head that moves back and forth across the drive disc, also known as a platter. The head is mounted on the end of an actuator arm, which is moved by magnets located on either side of it. The head communicates its location on the platter to the disk drive’s system. This enables the drive to move the arm and the disc for optimal data transfer.
The most common cause of the click of death in a hard disk is when the reading head fails. In this instance, the head is no longer able to relay its position, resulting in the drive moving the arm back and forth across the disc. As this occurs, the arm hits stops — metal pieces designed to prevent it from traveling too far — and as it makes contact, a ticking noise is heard. This is what is referred to as the click of death.
A head crash is not the only source of the click of death. In rare instances, the arm magnets might fail because of a power issue. This can also cause the dreaded sound as the magnets apply an incorrect amount of force to move the actuator arm, causing it to bump into the stops.
In the case of some removable drives, the click of death is almost always caused by the drive improperly writing data to a removable cartridge. Much like a hard drive, the reading heads are not able to find the data on the disc. The heads are repeatedly inserted and removed from the disc cartridge as the drive seeks the data. This is also a clicking noise and thus is termed the click of death.
Whether there is a fix for the click of death is a question that is almost as common as the phrase itself. The best solution is for the user to always have a backup of the data, negating the need to attempt any type of repair. If no backup is available, the user has several options.
In the case of a removable drive, the user can obtain another drive. In almost all instances, this works because the failure is caused by the drive incorrectly transferring data. The cartridge itself, however, is fine.
For a hard drive, there are a few steps that can be taken, such as tapping the outside of the drive, which can sometimes dislodge a stuck head. Another method is freezing the disk for four to six hours, then attempting to use it again while it is still cold. This serves to force the platter to move slightly if it becomes stuck. Lastly, the user can plug the drive into another computer and attempt to read the data that way. More often than not, these fixes do not result in alleviating the click of death, because they are able to succeed only in the case of a physical defect with the drive.
Should these methods not succeed, there is one possible solution. If the data is important enough, the user can enlist the aid of a data recovery company, which can attempt to pull data off the drive platter or platters. The use of these services is typically a last resort, because the process tends to be very expensive.