If you have a new external hard drive, chances are that you don’t have a whole lot of important data on it yet. If you do, that will change things. If the lost data is important to you, and not just iTunes songs you can re-download anyway, you should search your computer, flash drives, and other discs to see if that data is already duplicated somewhere else. Fixing or replacing the hard drive is all you will have to worry about if you already have the data copied off.
If you are sure that you don’t have any copies of the data on the failed drive, whether it is external or internal, you need to assess the drive to figure out the correct plan of action. There are a few ways that drives can fail. Not all of them end in the loss of your data. A lot of your decisions depend upon how the drive was acting before it ceased to work.
Most drives that fail, fail because of some sort of internal mechanical damage or defect. Damages and defects need to be handled very carefully. Most of the time damaged hard drives will intermittently boot up or slow to boot up before it completely fails. If you haven’t heard any noises from your dead hard drive, chances are your data is safe and just needs a bit of fixing to work.
There are three main reasons why you can’t access your data on a ‘dead’ drive. It could be a logical problem, an electrical problem, or a mechanical failure. A common problem for inaccessible hard disks is software. Sometimes computers don’t have the drivers to recognize and mount certain peripheral disks. A lot of these errors stem from miscommunication between the machine and the way the drive is formatted. For instance, a drive formatted for Apple’s Time Machine is probably in the HFS format. It is similar to the universal NTFS format but not the same. If you plug that hard drive into a Windows machine, nothing will happen.
Drive formatting isn’t the only software issue. If you have inadvertently deleted important files on the hard drive, it will change the way it works, or in this case doesn’t work. The likelihood then is that all of the files are fine and intact, but the hard drive doesn’t have the correct files telling it how to boot up. To fix the problem, you will have to connect it to a different computer and mount it as a separate disk. There are lots of programs that can reconfigure your files, like DiskWarrior and TestDisk. If nothing else you can reinstall the OS or copy of the raw files without a full boot up. If you correct the software issue, your hard drive should be in good working order. Just be careful not to delete something important again. Again, we do not recommend making any self recovery attempts if your data is critical.
Another semi common problem that happens with hard drive is a failure on the PCB. There is a printed circuit board attached to the bottom of the hard drive. It controls the operations that the drive does. If the drive doesn’t spin up at all, there’s a 90% chance that something is wrong with the circuits on the Printed Control Board. If a major component on the board fails, your drive won’t respond at all. There is another problem that is closely related to a failure on the board, but it is more specific. Most PCBs have two TVS diodes that work like fuses. One is 5v and the other 12v. If you experienced a power surge before your drive failed, the over voltage probably fried these diodes. Typically if this happens the other components remain undamaged. The diodes would need to be replaced, but the drive and the data itself should be fine.
The last big reason to have an unresponsive hard drive is a mechanical failure, specifically the read/write heads. If your hard drive is clicking rhythmically or intermittently most likely the read/write head(s) have failed. This is a very serious hard drive failure, any attempt to self recover data during a failure of this nature always leads to more data loss. It’s not unlike hearing noises coming from your transmission, if you continue to drive the car in this condition it will deteriorate and lead to more damage. The critical difference is the valuable data that is on your hard drive.
If your drive isn’t completely dead, or its death was preceded by some nefarious noises, it will need some internal repairs, which are very complex. These kinds of repairs should not be attempted by the average consumer. This kind of disk surgery requires a lot of training, experience, tools, and room so clean that the air has no particles in it. If you value your data, it is worth the money to have it professionally removed, instead of doing it yourself and potentially erasing all of your data. For an internal drive failure, professional help is the only way to preserve your data from a hard drive.