Are you planning to sell or donate your old PC or Laptop? Read this before you discard, sell, or donate your system or storage drive—such as hard disk, USB flash drive, SD card, or an SSD—if you don’t want to compromise your data security and privacy.

Data security and privacy go hand in hand. One is incomplete without another.

Larry Page once said,

“For me, privacy and security are really important. We think about it in terms of both: You can’t have privacy without security.”

When you delete a file from a hard drive or any other flash storage media, only the address from the Master File Table (MFT) database gets deleted. The operating system (OS) marks the sectors (from where the file is deleted) as unallocated. The OS then uses the unallocated sectors or memory blocks to store new data. However, the deleted file actually stays on the hard drive even after permanently deletion or emptying recycle bin folder.

Why Should This Concern You?

The deleted data could be personal files, confidential documents like credit card, passport etc or videos and photographs that you would never share with anyone. But unfortunately, if you haven’t use a file eraser algorithm or software to erase the data or wipe the free space (unallocated space) after file deletion, your deleted data can be easily recovered with a professional data recovery software. Therefore, it poses a grave threat to your data privacy.

Also, data containing sensitive information such as your browsing history, bank login details, passwords, transaction details, chat messages and application or system traces can also be recovered—even if you clean your system or browser cache using tools like file cleaner or cache cleaner.

That could be a nightmare for most users and a serious privacy concern. And if you are one of those who is concerned about their privacy and data security; then read along to know how you can get rid of your personal or confidential data by wiping the free space on your hard drive—that might contain previously deleted sensitive files.

How to Wipe Free Space on a Storage Media

1.    Use Command Prompt

Command Prompt in Windows can be used to perform various high-level and low-level tasks via command line interface. But did you know that you can also use CMD to wipe free space on Windows 10 without damaging your existing data?

However, in order to wipe the free storage space on a drive, you need to download the SDelete app (weighs just 151KB) from Microsoft’s official site. The SDelete runs via the CMD command line.

After downloading the SDelete app, follow these steps to sanitize the free space on your hard drive:

1. Copy the SDelete app in the root of the drive where you wish to wipe free storage space
2. Open the Command Prompt utility and type the drive letter that contains the SDelete app followed by the ‘Enter’ key

Example, type D: and press the ‘Enter’ key if the drive letter is D

1. Now type the following command to wipe the free space on the drive volume

sdelete –c D:  

1. Wait for the process to complete

The process is simple and easy to follow which successfully wipes the free space on your selected storage media—destroying deleted data beyond the scope of recovery.

2.    Use Cipher Command

Cipher command is another way of destroying deleted data permanently by wiping the free storage space of hard drive, sd card or other storage media. However, while running Cipher command, it’s recommended to quit all running programs to avoid any issue. Then follow the steps given below to wipe free space containing previously deleted files and folders:

1. Open Command Prompt and type following command to wipe the free volume space

cipher /w:C

Change the drive letter C to the drive letter that requires free space wipe

3.    Full Format

When you format a storage media, the data goes invisible but remains on the drive. During quick format, only the MFT is erased and replaced with a new one. Therefore, actual files remain on the drive unless overwritten and can be recovered.

Whereas when you full format the drive, it overwrites each block on your storage media with ‘0s’ (Zeroes) and sanitizes data beyond the scope of recovery.

CAUTION: You should use this method on empty drive volumes to wipe the free space. Formatting a volume with files inside can lead to permanent data loss.

Surprisingly, a few professional software such as Stellar Data Recovery may still be able to recover partial data even after full drive format.

Therefore, it’s highly suggested that you use a file wipe program, which uses various advance algorithms to wipe free space on the drive.

4.    Using File Eraser Software

A hard drive eraser software not only helps you get rid of your confidential data but also let you wipe free hard drive storage space. An erasure software, such as DBAN, BitRaser for File, Eraser etc is entirely safe and secure to use as it does not let you erase or wipe system and program files in the C: drive of Windows 10.

In addition, this privacy safeguarding apps facilitates use 17 international algorithms such as DoD 5220.22-M (3 passes/7 passes), NATO, etc. And some of them generates certification that guarantees data destruction beyond recovery (may be used for complaince).

To wipe free space, follow these steps:

Unlike Command Prompt, these utilities facilitates permanent removal via a graphical user interface (GUI) rather than Command Line Interface (CLI).

Moreover, wiping free space with command prompt isn’t safe. Any typo in the command can be destructive for the data stored in the drive volume or for the entire PC.

Conclusion

To safeguard your privacy and ensure data security, always wipe free space after deleting file. Alternatively, you can use a file eraser software to get rid of your personal and confidential files permanently with just a few clicks. Alternatively, you can leverage Command prompt. However, if you are not familiar with command line tool like CMD, we recommend not to use it to avoid any damage to your system due to typing errors.