If you were trying to delete confidential data from your hard
drive or SSD, a malicious person could recover your files using data recovery
software or Windows
file history. So what to do to permanently delete a file
from your hard drive? Follow our elaborate guide to stay calm.
Let's
imagine that you want to
permanent Data Wipe
that contains confidential data such as business documents, your bank details,
administrative information, financial documents, a private conversation or
something else. In short, the things that you want to eliminate forever
and that no one finds.
Data Wiping Process
Normally,
you send the file
to the Recycle Bin, and then empty it completely. Faster,
you can also select the file from Windows Explorer and press Ctrl + Del to delete it without going
through the Trash.
Using
this method, you get the impression that your file is permanently deleted. However,
it still physically exists on the HDD or SSD.
A
file occupies a specific space on the disk, so when you delete a file from the
Recycle Bin, the file system (the library that organizes and stores files on
the disk) simply tells Windows that the space occupied by that file was left
free and can be used to store another file in its place. The file system
only deletes the reference in the file table, but not the file itself.
An
"X" file will remain on the HDD or SSD until another "Y"
file is created and placed in the space occupied by this old "X"
file. And even after that, it is still possible to recover the data from
the old file by studying the magnetic fields on the surface of the hard drive
tray.
In
short, when you delete
a file from the Recycle Bin, the data in the file is not removed
from the disk, but simply waits to be replaced. The
solution is to write random data to the disk space where the old file was
located. Therefore, nobody will be able to recover your file because only
the random data written on that file will be visible.
What happens to a file when it
is deleted?
We
leave you the two most common cases:
Hard
disk drives (HDD)
When
you delete a file on an HDD, it goes to the Recycle Bin. This gives the
opportunity to recover it in case it was accidentally deleted and needed again.
But
what happens when it is removed from the Recycle Bin? Not much really. The
file is not moving or going anywhere. In fact, when you moved it to the
Recycle Bin, it didn't physically go there either. All that happened was
an index was updated to say that the file is in the Recycle Bin, not the
Documents folder. The index is called the Master File Table (MFT) for hard
drives. Until the operating system puts data there, the data in the deleted
file will remain recoverable. It may take minutes, days, weeks, or months
for the data to be overwritten.
Solid
State Drives (SSD)
It
is not exactly the same for solid state drives. SSDs are always randomly
moving files. Therefore, figuratively speaking, if you delete a file from
location 2781, the deleted information can sooner or later be moved to another
random location, until at some point the SSD finally decides to overwrite that
file.
So how do you select old file to
be safely deleted on SSD drive?
Well,
you really can't. A group of engineers from the University of California
studied how difficult it is to erase data from an SSD drive. What
you can do is make sure that you encrypted your SSD and that you have a TRIM
capable SSD. This is not a problem for most people, but you may be concerned
that people can still access that deleted information.
The least secure Data Wiping method
Just
delete the file in Windows Explorer and empty the Recycle Bin. Unless you
think someone will come up with data recovery software and search for that file
at some point, this will probably be pretty safe for most people.
However,
this is the easiest way to leave the deleted files on your disk so that they
can be found through specialized software. We already made this clear at
the beginning of the article, right?
Software to delete files on an
HDD
To
do this, you must use file shredding software. There are several, but if I
recommended one to permanently erase your files, it would be Eraser. By
default, Eraser uses the Guttmann algorithm, which writes patterns several
times in the space containing the data to be destroyed. This algorithm
ensures that your data cannot
be recovered.
We
leave you a small tutorial on how to permanently delete a file or folder, with
the free Eraser software. Here we go!
Simple erase with Eraser
Simple
removal from Windows Explorer: removal starts immediately or when Windows
restarts, using the default removal method and the right mouse button,
selecting “Erase” and “Options”.
An
information bubble will appear in the notification bar once the file has been
permanently removed from the hard drive.
Advanced
erasure with Eraser
Advanced
erasing by creating a task from the Eraser interface. This method offers
more possibilities: choose the delete method, schedule the Data Wiping at a specific
date and time, choose the type of items you want to delete (file, folder,
trash, unused disk space, and more).
Before
you start deleting a file and whatever method you choose, go to the Eraser
settings to define the delete method.
In
the default Data Wiping
method, choose the default delete method for your files and folders. Erasure
methods are ranked from top to bottom, from the most efficient (Gutmann - 35
passes) to the most superficial
With
the Gutmann method, you have the assurance that your data will be completely
erased from the hard drive, making it impossible to recover it. However,
this method takes a long time, since 35 passes are made in the area to be
erased. On the contrary, the Pseudorandom Data method is very fast, but it
does not guarantee a permanent Data
Wiping.
In
the default unused space erase method, choose the default erase method to be
applied to unused disk space (feature available with advanced erase).
Open
Eraser, click on the arrow to the right of the "Erase Schedule"
option and select "New Task" (shortcut: Ctrl + N).
·
You must define the following properties:
·
Task name (optional): this is the name you want to give your task,
and it is optional.
·
Task Type: when you want to execute the task, being able to choose
between manual, immediate, restarting or recurring.
·
Data to erase: data to be permanently erased.
·
If you select “Recurring” to delete files on a schedule, go to the
“Schedule” tab to configure the schedule settings and select when to start
deleting: Daily (every day), Weekly (every week) or Monthly (every month).
In
the "Task" tab, click on the "Add data" button to select
the items you want to remove:
·
File: a specific file.
·
Files in folder: all files in a folder. Check the Delete
folder if empty box to delete the folder as well and not just its contents.
·
Unused Disk Space - Unused disk space on the hard drive. We
have seen before that a free space does not mean that there are no files on the
hard drive, just that these files are waiting to be replaced by later files.
·
Recycling Bin: the Recycling Bin itself.
·
Secure move: move the file to another location without leaving a
trace.
·
Drive / Partition: select the partition you want to delete.
You
can also select the erasing method in “Erasure Method”.
Double
click on OK to confirm the final Data Wiping, depending on
the options you just defined. Eraser tells you in its interface when the
tasks will be executed next time (in the Next Execution column).
If
you have decided to
manually delete a file or folder, you should start deleting by
right-clicking on the task and selecting Run now.
The
status of the task changes to Completed when the files are deleted.
Other
applications for Data Wiping
With
their hard drives, some people try to recover deleted data, for example with
software like Recuva. Others point to the exact opposite: ensuring that
deleted files are no longer
recoverable at all. For this, there is nothing better than
resorting to secure erasure software.
Thanks
to the kind of software, not only are files and folders that are basically
deleted no longer recoverable, but formatted and partitioned disks also lose
all traces of your old data. At least that's what the developers promise.
Clean Disk Security
It
is a shareware (the license costs $ 19) whose interface (in English) makes it
easy to carry out a set of secure
erasure tasks. Simply check the desired options (out of a total
of ten), choose the method and click the "Clean" button.
As
in Eraser, there is a "Clean standard free space" function, but
apparently no function to safely
delete existing files. For security reasons, the developer has
chosen to install this option in the Windows context menu, by right-clicking on
a file or folder.
Clean
Disk Security also provides a tool to view the content of each sector of the
disk from the "View" button, a slightly more technical option that
may be useful.
Prevent Restore
It's
the free version of the Prevent Restore Pro software, which costs about $
14.95. In this lighter version, only one deletion algorithm is proposed,
which consists of replacing the deleted data with spaces.
The
software is easier to use than Clean Disk Security, and even easier than
Eraser, since you only need to answer a wizard's questions to start a safe
removal procedure.
Note
that here you can only permanently delete what has already been deleted: if
necessary, you will need to delete the content you want to delete before
starting the software.
Despite
its limited functions and erasure
methods , Prevent Restore is an interesting option that can be
sufficient within a company, for example to clean a reconditioned workstation
to move it from one department to another.
C-Cleaner
If
you know CCleaner, you probably know that it is not secure erasure software,
but a Windows optimization tool. It is used in particular to remove (in a
traditional way) temporary files from browsers and to optimize the Windows
Registry.
CCleaner
is nevertheless an interesting option here, as it is equipped with a disk erasure module. Which
may be enough for your needs?
Everything
is very simple here: you choose what to erase (free space or all), how (with a
simple to very complex algorithm, from 1 to 35 passes) and where (in which
drive). And that's it.
The
advantage of choosing CCleaner to secure your hard drives is that the software
is available in a portable version. You can copy CCleaner Portable to a
USB stick and thus have a ready-to-use eraser tool in your pocket and just one
click away.
Also,
the interface is in Spanish.
Data Wiping on solid state
drives
Solid
State Drives (SSDs) are becoming increasingly popular and it seems like it's
only a matter of time until they replace conventional hard drives in computer
systems.
SSD
drives work differently from hard drives, especially when it comes to drive
read and write processes. The most efficient way to safely remove hard
drives (overwrite space with data) becomes unusable on SSD drives due
to their design.
Data
on hard drives can be erased by overwriting them. This ensures that the
data is not recoverable by data recovery tools. This method does not work
on SSD
drives as it is not possible to specify the location to overwrite. This is very problematic for computer users who want to give away
their computer or sell it to a third party, as the data on the SSD can be
recovered by the new owner.
But
for SSDs there are also erasure methods:
·
Official manufacturer utilities
·
PartedMagic
·
Delete files
·
Format the SSD drive
Official
manufacturer utilities
Erasing
any trace of an SSD is more complicated. However, also in this case we can
use different methods. The first is to use the SSD manufacturer's
utilities. Each manufacturer of SSDs includes software with their products to
be able to manage the data and functions of the disk. These are the main
utilities that SSD manufacturers include:
·
Solid State Toolbox
·
Corsair SSD Toolbox
·
SanDisk SSD Toolbox
·
Samsung Magician Software
·
OCZ Toolbox
Using Parted Magic
Another
way to delete data on an SSD is Parted Magic. This is very effective
software that costs around $ 12.
Delete files
This
is a direct way to delete
files on the solid state drive from the operating system. It
is the only option that can be used to selectively delete files and folders. Deleting the files directly in Windows Explorer is not enough to
protect data from recovery software, as software like Recuva can find almost
100% of the files that have been deleted in Windows Explorer.
Deleting
files directly in the operating system is therefore not an option to
permanently delete sensitive data on solid state drives.
Formatting
the Solid State Drive
This
is the easiest option, as it can be run directly without the need for
additional software. Windows users should locate the SSD drive in Windows
Explorer, right-click on it, and select "Format" from the available
options. It is important to uncheck the "Quick Format" option to
make sure that all data on the drive is formatted. Windows Explorer does not display any files on the drive after the
full format is complete.
Recommended method to erase
data on SSD
Many
recommend formatting the
solid state drive as it is the easiest method of all. Generally, it is not
necessary to encrypt the data on the drive before formatting it, as it produces
the same results as doing a standard format. It is highly recommended to
test the result with a file recovery software to make sure that the excess data
cannot be recovered.
Conclusion
In
this tutorial we saw several methods that allow you to permanently delete a
file or folder from an HDD or SSD.
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