How to Securely Delete Files from your Device

If you’re planning to sell your old phone or laptop, then handing it over to a stranger without safely deleting your personal files can be risky. Smartphones and hard drives contain a lot of personal data and simply deleting those files isn’t enough. If you don’t want the new owner of your device to access your personal files then you need to do something more than just pressing the “delete button”. When you delete a file and even erase it from the recycle bin, it may seem like it’s gone for good. But your personal data like photos, videos, and other confidential documents isn’t gone until you randomly save another file on top of that same spot. Your deleted data can be recovered because the system doesn’t completely remove the file from your hard drive when you delete it.

How to Securely Delete Files from your Device

When you delete a file, Windows or Android simply marks that space as empty and you think that the file doesn’t exist anymore. This means that the file isn’t removed from your storage drive but only the reference to the file is removed. It stays on your device until it’s written over by another file. If your device ends up in the wrong hands, your deleted data can be recovered with the help of a disk maintenance tool or a data recovery utility. There are also professional forensic data recovery professionals who have the tools and technical know-how to retrieve deleted data even if it’s overwritten. If fragments of the deleted file still exist, a data recovery expert can recover the file even after it’s overwritten.

Secure Data Deletion
Simply dragging your files to the Recycle Bin or pressing “Shift + Del” isn’t going to permanently delete your files. Even actions like quick formatting the hard drive or performing a factory reset may not help in getting rid of your data. When you delete a file, only a small bit of information is erased that points to the location of the file. The original file stays on the drive unless you follow a stringent secure data deletion process.

On Windows and Mac, when you delete a file, the operating system only erases the path to a file so that it is no longer displayed in the Explorer or Finder. This data can be retrieved by a data recovery professional or software tools. However, if you use a secure delete application, it is possible to overwrite the deleted files with meaningless data. However, there’s still a possibility that a professional data recovery engineer can recover files that were overwritten. So, it becomes crucial to use the right third-party deletion or shredding tool to safely delete your sensitive information. Now, let’s find out how to securely delete confidential data to keep your information safe.

WINDOWS
The process of securely deleting data from a device depends on its operating system. If you’re using Windows 7, you can use the Cipher tool from the command line by pressing Windows + R and enter cmd. To delete a specific file or folder, enter cipher /w: [folder or file name]. To permanently delete a file, it’s important to overwrite it several times. That’s why it’s better to use software applications like Secure Eraser or File Shredder that are specifically designed for Windows devices. These software tools overwrite the files on your device multiple times to ensure that it is completely gone. However, if you’re using an SSD (solid-state drive), you need to find a tool that supports the secure deletion of SSD data with the Secure Erase function. With the help of the Secure Erase function, the SSD controller resets all storage cells as empty and wipes all data that might have left after formatting or deletion. These tools delete selected files and overwrite the free disk space to make data recovery impossible.

MAC OS
If you want to delete your data beyond the reach of even the most qualified forensic professional then it’s important to ensure permanent deletion. Mac OS comes with built-in tools to securely delete files. Users can go to the Secure Empty Trash option, or the secure erase options in Disk Utility. The “Secure Empty Trash” option allows overwriting all the files in the trash with junk data.  For the new Macs, there are third-party applications that can be pointed to the files you want to get rid of to delete them forever. All these programs overwrite the vacant space on your drive with random data to make the original files and folders irrecoverable.

The process of secure deletion is different for devices that use solid-state drives. SSDs work differently than HDDs, so the process of data deletion is also different. SSDs don’t give users control over where data gets saved. SSDs store bits of data at random locations around the disk and that means overwriting won’t work. For this reason, SSDs need to be encrypted so that no one can read what’s on your computer or recover erased files. To ensure that your files are encrypted, open System Preferences,>Security & Privacy> turn on the FileVault to make your deleted files inaccessible. You may also use a third-party program to encrypt your disks. If you’re planning to sell your device, then you may take back up of required data and then fully reinstall the operating system to securely wipe all the data on the SSD.

Tablets and Phones
Most of us store personal data on smartphones and tablets. Similar to SSDs, these devices also work on flash storage technology. This means that to securely delete files, users need to encrypt the data on the devices. If you want to sell your old phone, then perform a complete factory reset to wipe everything stored on it. iPhone users can go to the Settings and choose the Reset option within the General menu to delete all data. So, phone or tab users need to encrypt the device, remove the SIM card and any storage cards, remove any remaining account associations, and perform a factory reset. Unless your phone ends up in the hands of forensic data recovery experts, it’s extremely difficult to retrieve data after a reset.

If you simply want to get rid of your device, wear safety goggles, take a hammer, and smash your phone or hard drive into pieces. Another option is seeking the assistance of a company that provides secure media disposal and destruction services for all media types. The professional who offers data recovery services may also help you securely delete files by using powerful magnets to make data irretrievable.