Once a hard drive fails or has been damaged, attempts to fix the device without proper expertise will likely inflict do more damage and put stored information in greater jeopardy, storage experts say.

Kroll Ontrack this week released a list of common hard drive revival gaffes that the data recovery vendor warns against. That list of no-nos includes using of a hairdryer to "dry out" a wet hard drive, cracking open a drive to "swap out" the parts thought to be bad, and banging the device against a desk or hard surface when a drive's spindles go silent.

Although stubbornness and inquisitive human nature share some blame, the effort to save money is the biggest culprit leading untrained individuals to try their hand at data recovery, said Greg Schulz, an analyst at The StorageIO Group.

"In the race to save cost, [people] may forgo a data-recovery service and instead spend time to rebuild and restore [a drive that] actually ends up costing more in the long run," said Schulz.

Kroll claimed that more than 30 per cent of nonrecoverable disk drives are caused by human error rather than hard drive malfunctions.

The data recovery company said there are usually two types of people who attempt to fix nonfunctioning drives: novices with no disk drive or storage device knowledge and highly trained individuals who are "very motivated to fix the problem," said Jim Reinert, vice president of data recovery and software products at Kroll Ontrack.

Reinert said hard drive owners underestimate how complex a spinning hard drive is and wrongly believe its parts can be easily interchanged with off-the-shelf components. He said these higher-capacity storage devices feature new levels of drive-specific customization and factory fine-tuning that are not easily duplicated.

Among the biggest revival missteps, said Reinert, is to thoroughly dry a hard drive doused in water or some other type of liquid. Instead, Kroll recommends keeping the drive wet and immediately placed in a Ziploc bag for protection. "If it's wet, keep it wet. If it dries out, it leaves residue on [the drive's] heads and platters that are more difficult to recover," he said.

Aside from physical signs of distress, other clues a hard drive may be failing or damaged include an unusual clicking or grinding noise that could signal that a head crash is inevitable, a drive does not power up, spin or react at all -- pointing to an electronics failure, or a drive that is spinning and appears to be working even though data is inaccessible. That can lead people to run a system-failure program such as CHKDSK, Mac Disk Utility or FSCK to remedy operating system errors.

Reinert suggested running those programs in read-only or safe mode to identify potential errors without starting any actions that could further harm data on a faulty drive.

Schulz said hard drive owners should undertake backups regularly to protect themselves from problems that could lead to "painful reconstruction" and loss of data.

That's easier said than done, said Ed Sit, a clean-room engineer at DriveSavers Data Recovery. "The thing almost nobody does is back up critical data before any work on a suspect computer is started. That is the most common and detrimental mistake all users make."