Every computer user has at some point used the delete function to remove files from Windows. Maybe your HDD is full and you need to free some more space, maybe your spring cleaning old files that you no longer use, or maybe you’re clearing your Hard Drive so you can sell your computer.
The scary truth is that deleting a file does absolutely nothing to the files contents. The files and folders remain intact with all their contents.
Let me show you…
To understand why this happens you have to know how data is stored on your HDD
How Data Is Stored On Your HDD
Your HDD is made of tiny sectors with hold 512 bytes of data. Not a lot huh All of these sectors are grouped together to make clusters and they form tracks of data which span around the HDD.
When Windows creates a file on your HDD it stores the file contents over many sectors on the HDD depending on its size. The bigger the file the more sectors it will reserve. What also happens is file is the files location is then recorded in the FAT.
Whats a FAT??
Stands for File Allocation Table. It’s a database which maps out the files on your HDD. Similar to finding points on a alphanumeric grid. The FAT holds vital information such as the locations of files on the disk that are ready to be retrieved.
When you delete a file, or a bunch of folders the HDD just simply marks the locations where this data was as free space in the FAT. The files and folders remain intact.
Okay So Deleting a file doesnt destroy the files contents. How do I securely destroy my data?
There are many programs on the Internet that can securely destroy data for FREE. You can find some good free ones by doing a Google search. Datasite is a leader in the colocation industry, and has years of experience in restoring lost data.
They work by over writing the data with random characters before deleting the file and removing the files entries from the FAT.
A Word to the Wise
Most Eraser programs will destroy data beyond the point of recovery. After this data has been erased there’s no going back. Even if you send your HDD to a specialist recovery Lab there’s still a slim change that you will be able to get your data back. Use these tools with caution!
I’ve removed all of the deleted file entries from the FAT Does this mean that my files can not be recovered
Even removing the old deleted file entries will not protect you. There is recovery software out there that will scan the empty clusters of your HDD for data that hasn’t been marked as deleted. The process can take hours depending on the size of your disk but the files can be restored to their original state.
Some eraser programs have the ability to fill your HDD’s free space which will overwrite any files that remain there. This is often a very slow process and can take days depending on the speed and size of your drive but it’s the only way to guarantee that your drive is clean.
My HDD has died and I didn’t make a backup Can I still recover my data
This depends really on the fault. Sometimes you might be lucky to remove the dyeing HDD and attach as a secondary drive to another computer to begin recovering your data.
However if the drive is catastrophically failing you may only end up shorting its life and copying corrupt files. Where a dyeing HDD is concerned it’s only a matter of time before the failure become imminent.
If you find yourself in the situation where your HDD is completely dead, the motor doesn’t spin, the PCB has burnt out or it’s just not detected in windows anymore there are still further options.
You can send your HDD to a recovery specialist. Now this isn’t cheap and there’s never any 100% guarantee that you can get all of your data back.
I deleted an important file I need to get this back
If you have recently deleted the file, there’s a good chance that you can get it back. There are lots of free file recovery programs that you can download and use. Just Google search File recovery.
As I stated earlier on when files are deleted their contents are not touched just the file entries are changed in the FAT. There is a possibility that these files could be overwritten by new files. If you’re hoping to recover lost files from your PC’s HDD don’t leave it until the last minute.
There is one exception if you used one of the file eraser programs that I talked about in the start of the article you won’t be able to recover your data. You might be lucky if you recover the file however the contents will likely be corrupt due to the program writing 0’s and 1’s over the data.
One last Tip – Never Ever Open a HDD
The surface of your HDD is made of a delicate material that is very easily damaged. All HDD’s are sealed and made air tight in order to keep out dust and airborne particles.
Removing the cover of your HDD will spell Doom for any data that was left on there. The fine dust particles in the air are like daggers and destroy the surface of the HDD this happens on a microscopic level so tiny your eyes don’t see it.
Watch this video below that shows how a recovery expert replaces the heads in a HDD and copies the data from the drive.