Wipe free space or unallocated space

by William / Thu Nov 08 2018

Table of content:

What’s free space and unallocated space, how can I tell the difference between them, how to create such space on need? Can they store data? If they can, how can I wipe data clean from them?

Free space 1: is created when you delete a logical partition from the Extended partition, confused? Don’t be, open Disk Management, and check the bottom of the window, Extended partition is in a green border, partitions inside of it are all logical drives, delete one of them, you’ll get Free space, like the screenshot below, which cannot be used to extend E Drive if you don’t want to convert the entire disk to dynamic. Yes, the Extend Volume function in the right-click menu of E Drive is activated, but when you click on it and follow the Extend Volume Wizard, you’ll get the convert to dynamic disk prompt. Don’t confirm if you’re not sure what it is.

Disk Management Free space
Free Space in Disk Management

Free space 2: is the unused space on a partition, it’s the general meaning of free space, which we can directly access and use, like paste files into it. What am I talking about? well, right-click on the drive in File Explorer and click “Properties”, the Free space in color gray, like the screenshot below is what I’m trying to explain.

File Explorer Free space
Free space in File Explorer

Unallocated space, on the other hand, is created when you delete a primary partition, in Disk Management, it’s the dark blue blocks, delete one of the partitions in the screenshot below, you’ll get unallocated space, which can be used to extend the partition ahead of it, in this case, when you right-click on C Drive, you can use the Extend Volume function, it will consume the unallocated space and make C Drive a larger drive, and it won’t convert the disk to a dynamic one.

Disk Management unallocated space
Disk Management unallocated space

Can Free space and unallocated space store data?

Yes, they can keep data even after the partition on it is deleted, since the ‘Delete’ operation only removes the headers of data, not the body nor the content of it, any data recovery software is able to pick data up effortlessly. The same effect to format, the default format (quick format) method does more than the ‘Delete’ operation, but not that much to make data clean, data traces and contents are still visible in front of recovery programs.

And No, if you mean to directly store data on them, Free space and Unallocated space are not listed in the File Explorer, we cannot access them, sure we can’t write data on them unless new partitions are created by them.

PS. New unallocated space on a new disk has nothing in it, Free space won’t come from new disk, it always comes from partition deletion

How to wipe free space and unallocated space

Before we get started, let’s figure out what’s the ‘Free space’ refer to when it comes to ‘Wipe free space’, it’s Free space 2, the unused space in a partition, not Free space 1. Now we can proceed to wipe it (we’ll share how to wipe Free space 1 too, read on)

Wipe free space

Method 1: Use the built-in tool

Windows its own has a method to wipe free space, 3-pass overwriting, with a command, detailed steps are as followed:

  1. Press Win+R and type cmd then hit Enter to open the command prompt
  2. Type cipher /w:c: to wipe free space on C Drive, replace ‘C’ with any other letter if you want to wipe free space on it, but don’t forget to delete all files and folders on that partition before performing this command
Microsoft Windows [Version 10.0.17134.165]
(c) 2018 Microsoft Corporation. All rights reserved.

C:\Users\Macrorit>cipher /w:c:
To remove as much data as possible, please close all other applications while
running CIPHER /W.
Writing 0x00
Writing 0xFF
Writing Random Numbers

Method 2: Data Wiper wipe free space

Cipher.exe uses 3-pass overwriting wiping algorithm, while Data Wiper provides more, 6 different wiping methods are available, 1-pass (2 methods), 2-pass (1 method), 3-pass (DoD 5520.22-M), 7-pass(DoD 5220.28-TD), 35-pass(Peter Gutmann’s Algorithm), the more pass to use the longer the process will take, quite obvious on large size partitions. In fact, 1-pass overwrite method is enough to ensure data clean, in Data Wiper, it’s the default setting.

Steps to wipe free space in Data Wiper:

  1. Run Data Wiper (we don’t have to install it, simply run it from the portable package) and click the Free space only option
  2. Choose a wiping method or use the default 1-pass method
  3. Click on a partition and click Wipe Now, confirm and Data Wiper will start to wipe free space on that partition
Wipe free space in Data Wiper
Wipe free space in Data Wiper

During the process, we can continue our job, but it’s best not to write new data to the partition Data Wiper is currently wiping free space on.

Try Data Wiper

Wipe unallocated space

Method 1: use Disk Management

Disk Management can’t directly wipe unallocated space, so we need to create an empty partition first and use the built-in tool cipher.exe to wipe free space on it, steps are like below:

  1. Right-click on the unallocated space and choose New simple Volume wizard
  2. Follow the guide and create a new partition on it
  3. Open command prompt and type cipher /w:<drive letter>
New simple volume function in Disk Management
New simple volume function in Disk Management

Method 1: Partition Expert wipe unallocated space

We can directly wipe unallocated space in Partition Expert, 5 kinds of data wiping scheme available, run the program from the package and use the steps below to wipe unallocated space:

  1. Click on the unallocated space and choose the function Wipe unallocated space
  2. Choose a wiping plan from the listed 5 methods or click OK to use the default one
  3. Click Commit in the main window and Partition Expert will start to wipe
wipe unallocated space function in Partition Expert
wipe unallocated space function in Partition Expert

That’s how we wipe free space 2 and unallocated space, you may have found the solution to wipe free space 1 after all these steps, Yes, we can create a new partition on Free space 1 and use the cipher tool or Data Wiper to wipe free space on it

Try Partition Expert