Hard Drive Data Loss Scenarios
Hard drive failures can occur under any operating conditions, and while newer drives use advanced components to maintain the longest possible operating life spans, they are still susceptible to mechanical wear and electronic damage.
This page identifies some of the most common failure scenarios for modern hard drives, grouped together by category.
Signs of Read/Write Head Failures
Hard drives utilize magnetic heads to read and write data. Read/write heads are extremely precise and can be offset easily by physical bumps, sudden power surges and even through normal operation. When a hard drive’s heads are damaged, the device requires repair in a certified data recovery Cleanroom.
Some signs of read/write head failures include:
Clicking and Whirring Sounds - The hard drive’s read/write heads may have trouble finding data and may repeatedly reset, causing a “click” sound during each attempt. Alternately, the read/write heads could come into contact with another physical component, resulting in additional noises. Whirring or grinding sounds can indicate that the heads are in direct content with the platters. This can cause permanent data loss, so users should avoid operating any drive that makes unusual noises.
Slow Operation - When the read/write heads begin to fail, the drive may still be able to access data by correcting for occasional errors. This can cause the computer to run extremely slowly, particularly when accessing large files. However, computers can operate slowly for many other reasons, so slow operation is not always indicative of an impending hard drive failure.
File Corruption - The read/write heads may not find portions of a file, causing localized or widespread file corruption. Corrupt files are only partially readable, and depending on the location of the corruption, file names may appear garbled or unreadable.
Because read/write head failures can cause permanent damage to the platters that store user information, it is important to promptly shut down any hard drive that shows any of the symptoms listed above.
Signs of Hard Drive Spindle Failures
The hard drive’s spindle spins the platters under the read/write heads. Failures can occur as the motor wears down, but can also occur due to sudden physical shocks (for instance, if a computer or hard drive falls onto a hard surface).
Signs of damage due to hard drive spindle failures can include:
Grinding Sounds and Other Noises - When a hard drive’s spindle malfunctions, the read/write heads are not able to maintain their distance from the platters that store user information. This is because the read/write heads depend on an air cushion in order to operate.
As a result, the read/write heads fail along with the spindle, directly contacting the data storage platters and causing a grinding sound. This is a severe symptom that almost always results in permanent file loss. Computer users should not attempt to operate a drive that makes clicking or whirring sounds under any circumstances.
Hard Drive Will Not Spin - Some spindle failures result in a complete lockup or “freeze” of the motor, which prevents the drive from operating. No files will be accessible. The hard drive may make a strange noise as the motor attempts to operate the spindle.
Hard Drive Does Not Power On - For some hard drive models, spindle failures can prevent the hard drive from operating at all. The user will not hear any sounds, and the hard drive may not show up as an attached device in the computer’s BIOS (or BIOS equivalent).
Hard drive spindle failures can be complex failures, since they vary in severity and can often result in damage to other components. The chances of a successful data recovery are high as long as the drive is not operated in a failed state for more than a few seconds.
Signs of Hard Drive Electronic Failures and Firmware Issues
A hard drive’s printed circuit board (or PCB) relays information from the read/write heads to the computer. The PCB is sensitive to electrical events such as power surges, and if a computer overheats, some components of the PCB may stop functioning properly. Hard drive electronics can also stop functioning due to excessive dust contamination or electrostatic discharge.
The PCB contains a portion of a drive's firmware, which tells the drive how to operate and how to interpret commands from the computer. When a hard drive's firmware is damaged, it cannot effectively locate specific pieces of data.
Signs that cause electronic failures and firmware issues include:
Drive Does Not Power On - This often occurs when components of the electronics board are entirely inaccessible; the drive does not make any noises and will not show up in the computer’s BIOS (or equivalent) as an attached device.
Drive Information is Incorrect - If a hard drive has extensive firmware damage, it may not be able to accurately report information to the computer. It may display a larger or smaller capacity, and in some cases, an incorrect model number.
The drive may appear physically fine, but will not be able to access files with any regularity. Because firmware issues can result in head crashes, you should shut down any computer that presents incorrect drive information as soon as is possible.
File Corruption - As the firmware of a hard drive can control the placement of the read/write heads, firmware damage can also cause file corruption. Files will be partially or completely unreadable, and file names may be incorrect. The computer may not be able to load its operating system.
When electronic damage occurs, the drive may not be receiving power at all, but the user should still take appropriate precautions to shut the computer down and remove all power sources before attempting to handle the hard drive. Because the PCB is especially susceptible to electrostatic damage (ESD), it is important to follow proper grounding procedures before touching the hard drive’s board.
Signs of Hard Drive Logical Data Loss Issues
Logical data loss events occur when a hard drive does not have physical damage of any kind. Most commonly, logical data loss is the result of software malfunctions or user error; viruses and other malicious programs can also cause losses in certain circumstances.
Below are some of the most common example sof logical hard drive issues that cause data loss. Logical issues can also occur when you install a new operating system or program. For this reason, many developers recommend making a full backup before installing new software.
Types of logical data loss include:
File Deletion and Overwrites - Users may accidentally delete important files, mistakenly believing that backup copies exist in other locations. On most operating systems, deleting a file will only remove associated entries in the file tables. The data still exists and is still recoverable, but if the drive continues to operate, it may overwrite data permanently.
Partially overwritten data is often recoverable, although some information may be missing from the recovered file. Fully overwritten data is usually unrecoverable, so if you believe that you have deleted important files, keep your hard drive completely powered down.
Data Corruption and Missing Files - As mentioned above, corruption occurs when a hard drive cannot finish writing data to a file or when incorrect information is written, preventing normal file access. This can happen when a computer is suddenly shut down or when a program fails due to an internal error. Corruption can also occur if an external hard drive is suddenly unplugged from a computer without proper dismount procedures.
The symptoms of data corruption can vary, but in many instances, files will not open properly or will disappear entirely from your computer’s directory structure. You may see garbled information or file names. In many cases, corrupt data can be easily recovered by trained technicians.
Virus Damage - Some malicious programs (viruses, Trojan horses and various other types of malware) will prevent access to files. While few programs can make data permanently unrecoverable, virus damage can be serious, and ridding the computer of the virus will not always restore access to the data in question.
Types of Environmental Damage for Hard Drives
Some of the most severe hard drive failure scenarios occur due to unexpected disasters and weather events. Without exception, these failures will need to be treated in a professional data recovery laboratory.
Types of hard drives environmental damage scenarios:
Fire Damage - Fires can melt electronics, and the likelihood of data recovery will depend on the heat of the fire and the hard drive’s proximity to the flame. If a hard drive’s platters are intact, data recovery is very likely. However, fire damaged hard drives need careful treatment in a Cleanroom to limit additional damage due to platter contamination.
Smoke Damage - Smoke can carry contaminants into a hard drive, overwhelming the built-in filters that stop tiny particles from reaching the platters. This usually occurs when a hard drive is near a fire or near a controlled smoke source for an extended period of time. The hard drive’s platters will need to be cleaned in a certified Cleanroom to allow for a successful recovery.
Water and Liquid Damage - Water can corrode electronics, and when a hard drive is submerged during a flood or other disaster, it requires immediate treatment to limit the extent of this corrosion.
The drive will need to be thoroughly cleaned in the data recovery laboratory (computer users should not attempt to clean their hard drives on their own to avoid damaging sensitive components that may have been weakened by contaminated water). If the hard drive was not completely submerged in water, it will likely suffer electronic damage, but the platters that store the user’s data will be fully intact.
When a hard drive fails or shows signs of an imminent failure, the best practice is to disconnect any power sources and leave the drive powered down until you can contact a data recovery expert. Because hard drives are extremely complex devices, any attempt to repair or recover the drive will likely result in additional media damage.
Hard drive data recovery technology is extremely advanced, and the likelihood of a successful recovery is typically high -- however, excessive media damage or complete file overwrites can cause permanent file loss, so you should take appropriate caution to limit your risks.
Some types of failure can affect multiple hard drive components, and the only way to positively identify the source of a failure is to set up a professional diagnosis.