Most people believe that deleting files and emptying the Recycle Bin permanently deletes them, but this is not the case. These “deleted” files are still on your drive and can be recovered using recovery tools. So how can you safely delete sensitive data? You can use sDelete, Microsoft's data erasure tool.
Why deleting a file doesn't actually delete it
When you delete a file normally, it is moved to the Trash, which you can empty later. Using Shift+Delete walks around the basketbut in both cases the data is not actually erased. Windows simply removes the reference to its file system and marks the space as available. The data itself remains on the disk until it is overwritten by new files.
This means that if someone uses a recovery tool like Recuva, Disk Drill, or advanced forensic software, they will still be able to see and recover that file. So, if you sell or give away your laptop or hard drive after deleting documents, photos, financial reports or other sensitive files, the new owner can restore them as long as nothing new has overwritten that space.
Even if you just want to prevent other users from accessing your files, regular deletion methods won't work. To safely delete data, you will need a special Microsoft tool: sDelete.
sDelete (short for Secure Delete) is a powerful but often overlooked command line tool in the Microsoft Sysinternals suite for permanently and irreversibly deleting data. Instead of simply marking the file as deleted, sDelete overwrites the underlying data on the drive, making recovery nearly impossible.
Due to this deep rewriting process, even advanced forensic tools cannot recover deleted data. And because sDelete is developed and supported by Microsoft, it's much more secure than many third-party “secure erase” utilities. It overwrites the exact sectors where your files once existed and also removes the metadata that Windows usually leaves behind.
sDelete is most effective on hard drives. It also works on SSDs, but because SSDs constantly remap storage blocks and use TRIM, sDelete can't guarantee to overwrite the exact physical cells where your file was stored, so it deletes as much residual data as the hardware allows. However, sDelete removes traces left by standard deletion, allowing for a safe cleanup.
How to set up sDelete for the first time
sDelete is not included with Windows by default, so you will have to download it manually. Go to Microsoft Sysinternals websitedownload the sDelete zip file, save it to your computer and extract it to C:\Program Files. Next enter Viewing advanced system settingsopen the mapping result, go to the Advanced tab and click on Environment Variables.
In the System Variables section, select the Path entry and click Edit. Select New to add a new row, then click Browse to select a folder. Go to C:\Program Filesselect the extracted folder sDelete and confirm the selection by clicking “OK”. This will update your system's PATH and complete the basic sDelete setup.
How to use sDelete to permanently delete files
Since sDelete is a command line utility, you can use it through the command line. Open Command Prompt as Administratortype deleteand press Enter. You'll see available options that you can use to safely remove and clean up your drive. When you launch it for the first time, a license agreement will appear—just click “Agree” to continue.
To safely delete a file using sDelete, first copy the full file path. Navigate to the folder containing the file, right-click it and select Copy as Path. Then open a command prompt, type sDelete then provide the full path (including file extension) and press Enter. For example, to delete a file named HTG.txt, type sDelete, paste the path, and press Enter—the file will be safely deleted.
To remove an entire folder along with its subdirectories and read-only files, use the -s and -r options before the folder path:
sDelete -s -r
This command will display the number of directories and files removed.
By default, sDelete overwrites the space once to make recovery more difficult. To increase the number of rewrites, use the -p option followed by the desired number. For example, to delete a folder with all subdirectories and read-only files while overwriting it four times, use:
sDelete -s -r -p 4
Other ways to safely remove an SSD besides sDelete
You can rely on sDelete to securely delete sensitive files on a drive that you will continue to use, especially if it is a hard disk drive (HDD). However, for solid state drives (SSDs), the safest method is to enable Full disk encryption with BitLocker and then securely delete the encryption keys, making all previously stored data inaccessible.
If you plan to sell or give away your computer, it is better to use Built-in Windows reset tool. Right-click the Start button, open Settings, and select System > Recovery. Click Restart your computer, select Erase everything, and follow the instructions to securely erase all your data.
If you ever thought that deleting a file completely removed it from your drive, now you know that it doesn't. sDelete is powerful, but you don't have to use it every time you delete—reserve it for sensitive files. Also keep in mind that files deleted using sDelete cannot be recovered even with advanced recovery tools. Therefore, you may lose data if you delete the file by mistake.
