Inside every hard drive are one or more platters (usually glass) coated with magnetic material. The platter is spinning at 4,200 to 10,000 rotations per minute. Just like a record player sped up a hundred times. There are tiny read/write “heads” floating over the platter on delicate arms.

The instance from head to platter is less than the breadth of a human hair. If the head accidentally touches the platter, it acts like a snowplow, scraping the magnetic material and your data off the platter. Forever. That’s just one way they can fail.

Mechanical failure of the drive caused by being dropped, bumped while in use, or manufacturer defect; data corruption or directory damage caused by forgetting to eject disks before removing them, computer crashes, viruses, power loss, or plain bad luck.

Accidental deletion or files by emptying the trash, reformatting the hard drive, or reinstalling the operating system.

Environmental disasters like fires, floods, power surges, or extreme heat and humidity.

The computer’s operating system (OS), is responsible for reading and writing data to your drives.

Besides writing the actual data, the OS has to update the indices that keep track of which file is where. If the computer crashes, loses power, or experiences another problem, it’s possible that a file is written properly, but its index gets corrupted.

It’s best not to move a computer while the drive is spinning. Ideally, you would put a portable computer to sleep before moving it. Properly ejecting disks makes sure that their directories are properly updated before you disconnect them.

If you are shutting down the computer, you don’t need to eject disks. The OS will take care of properly updating each drive before it actually shuts down the computer. So, directory damage is usually not your fault, and you probably can’t prevent it, but you can help.

You may be able to recover some data depending on how your files were lost. If you don’t know how your files where lost, getting professional help is always your best option.

Mechanical failures: Software cannot fix a mechanically failing drive (ever).

Running these utilities on a failing drive can quickly destroy data, which could have been professionally recovered.

If you are not backed up and your data is essential, we recommend using a professional data recovery service. Read the next question for our thoughts and warnings on repair utilities.