What is the reason why deleted files can be recovered?

When a file is deleted, it is not actually removed from the hard drive. Instead, the operating system simply marks the space that the file was occupying as available for use. The actual file remains on the hard drive until it is overwritten by new data. This is why deleted files can be recovered—they have not actually been removed from the hard drive.

How does the process of file deletion work on a computer?

When a file is deleted on a computer, the operating system marks the space where the file was stored as available for use. The actual data in the file is not removed immediately and can still be recovered until the space is overwritten by new data. To securely delete a file, it must be overwritten by new data to prevent recovery.

What is a file system, and how does it relate to deleted files?

A file system is a way of organizing and managing files on a computer. It is responsible for keeping track of where files are stored, their names, and the data contained within them. When a file is deleted, the file system marks the space it occupied as available for use by other files. The actual data from the file may still exist on the hard drive, but the file system does not recognize it as part of the file system anymore.

What are the common file systems used in modern operating systems?

NTFS (New Technology File System): Developed by Microsoft, this is the most widely used file system for Windows operating systems. FAT32 (File Allocation Table): This is an older version of the Windows file system, but is still widely used for compatibility reasons. HFS+ (Hierarchical File System): Developed by Apple, this is the default file system used on Mac OS X and iOS devices. EXT4 (Fourth Extended File System): This is the most common file system used on Linux-based operating systems. APFS (Apple File System): This is a newer file system developed by Apple, and is used on macOS, iOS, tvOS, and watchOS devices.

What is the difference between logical and physical deletion?

Logical deletion is when a file or data is marked as deleted, but it still exists on the system. Physical deletion is when a file or data is completely removed from the system, leaving no trace of it.

How to Prevent Unwanted File Recovery

Read this article to find out how files are removed and why they can be recovered, how to recover deleted files – or remove them permanently.

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While files are just deleted from the hard disk in a conventional way, they don’t actually disappear – the information about these files remains on the hard disk even after you empty the Recycle Bin. It is this peculiarity that lets these files to be recovered – by you, or by other people… If you are not cautious enough, the removed confidential files can be recovered by other people, and used for purposes you may not like.

What happens when a file is removed

Windows tracks file location on the hard disk with a sort of labels. Every file and folder have this label that helps the operating system determine the beginning and the end of file.

When you delete a file, Windows removes the label and marks the sectors where file data is located as free space. From the viewpoint of the file system, such files are no longer present on the hard disk, and such sectors are believed to be vacant.

That is why such deleted files are available for recovery until Windows overwrites them with new information. A data recovery tool can scan the hard disk, detect such data and recover the files. If the data of such deleted file was overwritten partially, only a part of data will be recovered, which may render the recovered file to be damaged or bad.

With all that in mind, remember that the principles behind solid-state drives are different from those on which conventional hard disks are based.

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Why removed files are not erased instantly

Then why doesn’t your computer erase deleted files just as you remove them? Removing the file label and marking this disk space as free is a very quick operation. On the contrary, erasing file info from the disk surface by overwriting it is going to take much longer. For example, it takes almost no time to remove 10 Gb of files. However, erasing this data will take a few minutes – just as long as the computer needs to write 10 GB of information to the hard disk.

So in order to improve performance and reduce time needed to manage data, Windows and other operating systems do not erase data when deleting files. But if you need to erase file contents when deleting it, you can use a special eraser tool.

As we have already said before, solid-state drives (SSDs) work in a different way. All the things above apply to conventional hard disks (HDDs). While you are using an SSD with the TRIM feature enabled (it is present in all modern PCs), deleted files are erased in a second and can’t be recovered. An interesting fact is that external solid-state drives don’t work that way, but tend to treat deleted data just as their ancestors, HDDs.

The operating system erases files instantly to increase the speed of writing data in the future, and if the file data is not erased immediately, this will have to be done when saving new files to the disk – which is going to make the SSD slower, over time.

Recovering deleted files

If you deleted a file accidentally, here’s what you should keep in mind:

The file has to be recovered as soon as possible: Windows keeps on writing new data to the hard disk, and every minute increases the chances that the data you are worried about is to be overwritten. So to make the process successful rather than not, start the recovery action without delay.
Reduce using the hard disk to a minimum: the best way to recover a deleted file from a hard disk is to power off this computer, and connect its hard disk to another PC, then recover the require file from the operating system of the other PC. If you continue working with the hard disk that the file was removed from, you are taking a risk of overwriting it.

Windows has no built-in tools to scan the hard disk for deleted files. However, this drawback is compensated by a huge number of third-party products that do a great job of bringing your files back.

A utility for data recovery after formatting a hard disk will scan your storage device and get the deleted files back.

Partition Recovery™ 4.9

The tool recovers data from any devices, regardless of the cause of data loss.

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How to prevent unwanted file recovery

If there is some confidential or personal data on your computer, it could be important for you to make them impossible to recover and guarantee it will never fall into somebody else’s hands. If you are going to sell or lend your computer or hard disk, this is one of the things to take care of.

For this purpose, you can use one of the many tools for cleaning the hard disk that will overwrite all data on such disk and all deleted files will be destroyed.

However, even using such programs doesn’t always guarantee the desired result. You may erase a part of the hard disk or one of the local disks, while the other local disk may contain copies of the deleted files. That is why it is always best to clean all physical disks.

Bear in mind, though, that this process takes much longer than just deleting the files.

Now you know why and when deleted files can be recovered, and when they can’t. Remember about it when you decide to get rid of the computer or hard disk – because that hard disk may still contain confidential data.