I had a customer come in recently with a hard drive that was not working. It had all of his wedding videos on it. Before he came to us, he went to the IT guy in his office and the IT guy had tried to fix the drive. When that failed, he came to us. My heart sank. I knew that although his IT guy was trying to help, he may have permanently destroyed the irreplaceable wedding videos.
The most important thing to know about hard drives in distress is: Do not leave them running, do not try to run software to repair them. Hard drives that are experiencing problems will often make themselves worse and even destroy themselves if left running; about 15% of the time you will permanently destroy the drive so that even labs like DriveSavers cannot recover the data.
Here’s why. Spinning hard disk drives perform a variety of routine maintenance functions whenever they have time. They re-write bad sectors to new good sectors, they write logs, they scan themselves for problems. These are all good things when a drive is functioning normally. These are all dangerous things when a drive is in distress. When a drive begins to fail it can start to lose track of where things are on itself. It can begin to make mistakes. When a drive is in distress and it goes to perform its routine maintenance, it can cause even more damage. It may re-write bad sectors onto good sectors thereby destroying the data that was there and possibly breaking links to other data. The logs can be mistakenly written over good data thereby destroying it.
When you run software tools like DiskWarrior, you can cause the same problems. First of all the drive is running and can do the damage outlined above. Beyond that, when you go to fix the drive, if it is badly damaged enough it might write the fix, like a new directory on top of good data, thereby destroying it.
As it turned out, we were able to save the wedding videos. The drive had not been permanently bricked when the IT guy tried to help. This customer was lucky.
When your data is vital the only safe thing to do is to take your drive to a recovery specialist who will disable the drive’s automatic functions, make an exact bit-by-bit replica of every recoverable sector and then repair and extract the data.