If you’re like most people, you probably don’t think much about how Windows manages free space. After all, it just keeps track of how much space is used on your hard drive and offers to delete old files to make room. But there are a few things you can do to protect yourself from data loss and make sure your computer runs smoothly. The first step is to understand how Windows manages free space. When you install Windows, the operating system creates a default C: drive (the “C” stands for “computer”). Windows also creates a hidden D: drive (the “D” stands for “drive”) that’s reserved for system files and programs that are installed with Windows. The rest of your hard drive is divided into folders called “drives,” each of which is represented by a letter (A-Z). When you install software or create a document, Windows copies the files to the appropriate location on your hard drive. For example, if you install an application from the Microsoft Store, Windows copies the application’s files to C:\Program Files\Microsoft Store\AppX{application name}. If you create a document in Microsoft Word, Windows copies the document’s file to C:\Users<username>\Documents\Microsoft Word{document name}. Windows also keeps track of how much free space is available on each disk partition. When it detects that one of your drives has less free space than it should, it starts deleting old files in order to make room. If this process doesn’t remove enough files from one of your drives, then Windows will start deleting files from within programs and applications in order to make room. This can lead to data loss if you don’t take steps to protect yourself. To prevent this from happening, use Disk Cleanup regularly to remove old temporary files and unneeded software programs. You can also use System Restore or Time Machine backup services to restore your computer if something goes wrong and data loss occurs ..
Your data is important, but just because you have emptied your recycle bin doesn’t mean that the file can’t be recovered.
Note: This will work on both Windows 7 and Windows 8.
Securely Overwriting Free Space
When you delete a file from the recycle bin in Windows, rather than deleting the actual file, the space the file is occupying is simply marked as free so that another file can come and use those blocks on your hard drive. One way of making sure that your data is not recoverable is to simply overwrite all the free space with random data. To do this click on start and open an administrative command prompt.
When the command prompt opens type:
Where F is the letter of the drive you want to securely overwrite the free space on.
It will overwrite the free space with three passes as seen above.
First with all zero’s – 0x00 Second with all 255’s, – 0xFF Finally with random numbers
That’s all there is to it. It took about 25 minutes to overwrite 50GB of free space on my system, but your mileage may vary.
SDelete
Alternatively, if you want to make use of a third-party tool you can use SDelete from Microsoft’s Windows SysInternals suite of free utilities. Simply download the file and extract it.
Then open the extracted folder, type “cmd” into the navigation bar and press enter.
Now run the following:
Where F is the letter of the drive you want to overwrite the free space on.
That’s all there is to it.
