You might not know it, but when you delete a file from your computer’s recycle bin, the information on the file is still sitting on your hard disk somewhere. Not all of the data may be intact, and not all the data may be recovered, but still some of it could easily still exist on your computer, which could be a privacy risk for some.
It may seem to the casual observed as though the files are gone, but depending on your operating system and how much you save to your computer afterwards, your data may remain intact. If you picture your computer as a book, you might think that deleting a file is like tearing a page out and throwing it away, but that’s not quite the case. Instead, deleting a file is a bit more like allowing the pages of your book to be written over; your computer hasn’t destroyed the data completely, it has just made it possible to overwrite it on your hard disk. According to experts, data can remain on your computer for weeks or even months in this way.
It is possible to use programs specially designed to destroy deleted data, but even these programs are sometimes ineffective against computer-forensics specialists. These programs often aim at completely overwriting deleted data with a random sequence of zeroes and ones, or even with replacement data to appear less conspicuous.
Even if you wipe these files, most operating systems keep a second set of stored data with information such as file names and creation dates. According to computer forensics experts, even the most advanced computer wipes still leave enough data hidden on hard disks to be recovered after a dozen or more overwrites.