Today, let’s see how we can help you if you need to permanently delete files. If you are selling your old hard drive or passing on your computer to someone else because you just bought a new one, you might want to make sure first that all sensitive data is wiped entirely from your hard disk.
It’s a well-known fact that deleted files aren’t actually deleted.
First of all, there’s the Windows Recycle Bin. If you’ve ever deleted a file or a bunch of files by mistake, hopefully you were aware that Windows Recycle Bin still contained a copy of whatever it was that you erased out of your digital life.
The Recycle Bin is usually found on your desktop. (If you can’t find your Recycle Bin on your desktop, check our related Recycle Bin article).
Simply double-clicking the Recycle Bin would bring up a window with the stuff you deleted. In the Recycle Bin window, you can right-click any file or group of files and select “Restore” from the context menu in order to put the file back in its original location on your hard drive.
As long as your deleted files stay in your Recycle Bin, they will be very easily un-deleted. The capacity of your Recycle Bin is not unlimited, but can be controlled by right-clicking your Recycle Bin icon and selecting “Properties” from the context menu.
You can also right-click your Recycle Bin and select “Empty Recycle Bin” from the context menu to, um, … empty your Recycle Bin and clean up your deleted items.
Many people still think that emptying their Recycle Bin will permanently delete files from their system, but even now, these files are still not entirely deleted.
Not even close.
You see, what happens is that the *reference* to the file is taken away, so you will find no trace of the file in Windows Explorer, but the actual data bits of the file are still living on your hard drive.
You can compare this to a book with a table of contents if you will. You can take out the reference to a chapter in the table of contents, but the chapter itself can still be in the book.
If you empty your Recycle Bin, Windows will remove the references to the deleted files, but the actual files will still be there.
There is one subtle difference though.
Windows will mark the space that the files were taking up as available. That means that, if you start adding new files on your hard drive, the empty space originally taken up by the deleted files, could be overwritten by your new files.
As long as you don’t load any new files on your hard drive (for instance by downloading music from the internet or by unloading a bunch of photos from your digital camera), the actual data blocks of your deleted files will remain intact on your hard drive.
And that’s a security/privacy issue.
If someone gets his hands on your hard drive, all it takes to reconstruct your deleted files is a good un-delete tool, like Recuva.
If you want to permanently delete files on your hard drive, you will need to use a tool that finds the data blocks of deleted files and overwrite these blocks with random fragments of information. There are several tools available to wipe free disk space, most of which even offer the option of performing multiple passes of data-overwriting for increasingly higher levels of security to permanently delete files.
I always use Drive Wiper to wipe free disk space, which comes with CCleaner. (Don’t know CCleaner? Feel free to find out more in our CCleaner article).
In the screenshot below, you can see that CCLeaner’s Drive Wiper offers multiple security levels of overwrite passes.
With Drive Wiper, you have the option of selecting “Free Space Only” Wipe mode or “Entire Drive (All data will be erased”.
Finally, Drive Wiper will let you select the drive on which you want to permanently delete files.
Please note that you won’t be able to select your system drive if you’ve selected the “Entire Drive” option (your system drive is the drive that your Windows operating system is installed on). Obviously, Drive Wiper running under Windows can't wipe the drive it's running on. If you need to wipe your system drive, you can either boot your computer from a Drive Wiper bootable cdrom, or you can hook up your system drive as a secondary disk on another computer.
A bootable wiper to permanently delete files from a system disk is Darik's Boot and Nuke, more commonly known to as DBAN. You can download a bootable ISO DBAN file from dban.org (if you don’t know how to burn ISO files, please refer to our article about burning ISO files).
What a many people don’t know is that there’s a “hidden” feature in Windows that also offers the possibility to wipe free disk space: cipher.
Cipher is a so-called command-line tool, so you will have to open a command prompt in order to use it. You will need an elevated command prompt if you are running Windows 7.
To open an elevated command prompt in Windows 7, click on the Start button (Windows Start Orb) and type “cmd” (without the quotes) in the Windows Search Box.
A list of resulting programs will come up and at the top, right underneath “programs”, you will see
Right-click on “cmd.exe” and select “Run as administrator”
The image below illustrates once more the steps above to open an elevated command prompt:
In the elevated command prompt, type:
Where you substitute c: with the drive letter where you want to wipe free disk space. Cipher will take quite some time to run, as it will perform resource-intensive write operations in order to overwrite free disk space.
Another reason why you might want to know how to permanently delete files is because you don’t want to leave any traces of your internet history. Internet Explorer (or any internet browser for that matter) keeps track of the internet sites you visited. If you use its built-in function to delete your internet history (see screenshot below), please be aware that with a decent un-delete tool, your deleted internet history can still be reconstructed. Unless of course you permanently delete files from your internet history.
There’s an easy way to achieve this: use the Cleaner functionality of CCleaner to erase your internet history, followed by CCleaner’s Drive Wiper to wipe free disk space. All combined in one simple tool. See our CCleaner article to find out more.