Three Steps to Securely Wipe Files

Destroying sensitive information is easier said than done. If you’re about to retire an old hard disk or PC, or if you just want to get rid of files you no longer need (but which contain critical personal or business-data), then a simple format or file delete won’t help you at all. This blog post shows you how to securely wipe critical files from your system once and for all!

Why is it so difficult to delete files?

Windows (its file system, to be precise) is not capable of destroying data. If you want to get rid of sensitive data, deleting files or even formatting the hard disk isn’t enough. By doing so, you’ll just wipe all of the references (or pointers) to these files; the files’ data, however, will remain intact and can easily be restored using various data recovery programs.

Once you delete a file and empty the Recycle Bin, the data remains on the disk and is marked as free space which means that from now on, it can get overwritten. This happens when you install a program, download a file, or copy data on to your hard disk! But don’t count on it happening immediately—it can sometimes take weeks or months to overwrite your data. Here are three steps to instead, help you get rid of this data once and for all.

Step 1 – Delete Volume Shadow Copies

Windows creates Volume Shadow Copies of system files and some of your personal data (i.e. files residing inside your user folder located under C:\Users\Username). It’s actually a great way to restore previous versions of files like those you accidentally deleted. Unfortunately, it’s also a potential liability as these files can be restored.

Get rid of these Volume Shadow Copies by right-clicking on “Computer” and selecting “Properties”. Go to “System Protection”, select your system drive and click on “Delete”. This will delete all of the files that Windows currently keeps previous versions of—this includes your personal files and critical system files which are the basis for System Restore.

But beware! The next time your PC is idle, these Volume Shadow Copies will be recreated. If you’re in the habit of safely deleting files, you might just want to turn them off altogether by clicking on “Turn off system protection”. Be careful! This doesn’t just disable the previous version restoration feature–it also disables System Restore and can affect some backup tools (such as Macrium and Paragon) which rely on Volume Shadow Copies.

Step 2 – Safely delete files

To safely destroy data, we’ve created a wiping mechanism called TuneUp Shredder. It uses several algorithms which comply with data security standards and render files unrecoverable.

Here’s how TuneUp Shredder works:

1. Grab the trial version of TuneUp Utilities 2012 (if you haven’t already). This will add a new context menu item (TuneUp Shredder) to your Windows explorer. Simply right-click on the folder or file you’re trying to securely wipe from your machine and select this menu item.
   
2. Next, choose your algorithm! Now keep in mind that it is next to impossible to recover the data, even with the “Fast delete” option, since you’ll essentially be overwriting it. But if you want to be absolutely sure that this data is rendered irreparable, go with one of the more advanced methods. 
3. Hit “Yes” to delete the file.

Step 3 – Completely wipe a drive

Ready to give away a PC? Then it’s wise to perform a complete wipe of the entire hard disk. In the past, I’ve used and recommend either Active@ KillDisk 5.5 (the Pro version creates a bootable KillDisk USB key that you can use to destroy the data) or Darik’s Boot And Nuke. These tools overwrite your entire hard disk with zeroes or multiple writes of different characters (much like TuneUp Shredder).

Now, while this works well on mechanical hard disks, you’re out of luck if you have an SSD. SSDs’ data gets written and deleted in a very scattered fashion, and neither the user nor the operating system has control over where the actual data bits are stored—it’s all done by the SSD controller. This whitepaper proves that while some data can be destroyed (either by using some of the built-in mechanisms or third-party tools), in many cases, the data was still intact.

The only SSDs that can be safely wiped are those that include the ATA Secure Erase command. If it does, the Kingston Red Tech Blog provides detailed steps on how to perform a secure wipe of the hard disk using HDDErase (which issues the ATA Secure Erase command to your SSD firmware). If your drive doesn’t support this mechanism, you should try to fully encrypt your hard disk and delete the encryption key. Windows’ own BitLocker (only available in higher Windows Vista and 7 editions) is one possible way. If all fails, physically destroy the drive—pure brute force or some pyrotechnics might do the trick.