Deleting files using the default function in Android doesn’t remove the item, it only marks the space it occupies on the storage drive as empty. In other words, the OS ‘sees’ that space as being free, meaning it’s available to store new content you might be saving on your phone. As a result, the formerly deleted file will continue to ‘live’ until another file will be saved in the same location.
This is basically the same for any operating system, allowing specialized applications to recover the deleted information, as long as something else wasn’t stored on top of it. There are plenty of recovery apps available in the Play Store, so if you really want to make sure the files you delete are unretrievable, using the default removal function is simply not enough.
Luckily, just like data recovery apps exist, others have been designed to permanently delete it. This means the storage space where the deleted files were located is rewritten using random data to prevent recovery.
For the purpose of this guide, we’ll use a free app called Secure Eraser since it’s absolutely free and very reliable. To begin with, you’ll need to install it either by visiting the download link below or by searching its name in the Play Store.
After you install the app, launch it and on the main screen, you’ll have to configure a few settings before erasing any deleted files.
In the drop-down menu at the top-left of the screen, you’ll have to select where you want to rewrite the empty space – the internal or the external storage.
Also, the drop-down menu located at the top-right side of the screen, lets you choose the type of data that will be used to rewrite the empty space on your storage drive. You can opt to fill it with zeros (0000-0000), Fs (FFFF-FFFF) or with random data.
Once you’ve set everything up, simply tap the ‘Start’ button in the lower-left area of the screen and the empty space on the selected storage will be permanently wiped, making all previously deleted data unrecoverable.
Such tasks may take up to 15 minutes or even more, depending on the size of your storage so you might want to start this process when you don’t need to use your phone for a while.