How to properly erase a hard drive

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A quick click on the [Entf]Key and the file is gone. I think so. Because when you move pictures, documents, etc. to the recycle bin, the files are not permanently deleted. Even after emptying the garbage can, the data persistently remains on the hard drive. But how do I delete mine hard disk correct? We have summarized the most important information for you.

Why is my data not completely erased?

The fact that the data persistently remains on the hard drive even after emptying the recycle bin is due to the way a computer stores data. A file cannot be found in one place, but is distributed in different places on the hard disk. How does the PC find the scattered elements of the file? To do this, he is looking for the heel, the “table of contents” of a computer, after the corresponding reference. This then indicates exactly where the file is located.

If users now delete a file, they only remove the reference in the table of contents, but not the data itself. The operating system marks the storage space as “free” and only gradually overwrites the files with new information. Even a freshly deleted file can therefore remain in its entirety on the hard drive for some time and with it Recovery-Tools how Recuva or Photorec to be restored.

How do I securely delete my data?

If trash and emptying doesn’t help, what then? There are several options here. But be careful: not all guarantees 100 percent Success. Once important files have been backed up, the second step is to determine which hard drive is installed in their computer. Because depending on whether you have it with a classic magnetic hard disk (HDD) or one Solid State Disk (SSD) have to do, data is saved differently.

How can you find out your hard drive type? at Windows-PCs you can find the description in Control Panel> Device Manager> Drives. Somewhat modern Apple MacBooks usually only have SSD hard drives.

Erase HDDs

A magnetic hard drive makes erasing easier for users. Because the entire storage space can simply be overwritten – such a process will also be „Wiping“ called. Tools like Eraser (Freeware) take over the deletion process for users and overwrite the hard drive several times. This makes it difficult for unauthorized persons to restore the files.

If you want to be on the safe side, you can also use a program called DBAN Clear. This software comes into action before the operating system of your own PC becomes active and can therefore access the hard disk directly. For this purpose, users * use the instructions from DBAN to create a USB stick with which they can start the computer and begin the deletion process.

Erase SSDs

SDDs cannot be completely deleted. This rumor persists but is not entirely true. However, “wiping” an SSD is more difficult than deleting traditional magnetic hard drives. The reason: SSDs use so-called Flash memorythat wear out quickly. Controller chips are therefore built into SSDs that minimize write and read cycles in order to keep wear and tear to a minimum. This minimization ensures that the operating system cannot decide for itself which part of the memory is to be accessed during a deletion process. Therefore, conventional wipe tools such as CCleaner, Eraser and Co. are not reliable erasing options.

How can users still delete data on SSDs? Most SSD management programs contain so-called “Secure-Erase-Options“With which your own hard drive can be erased of information. Only the message “Disk Frozen” can thwart your plans. The “frozen status” means that the hard drive is protected from being erased. It is supposed to shield the hard drive from malware. The way out: an alternative, independent of the manufacturer, like the software Parted Magic. This wipe program works similarly to DBAN, but is tailored to SSDs.

Cleaning software and formatting – is that enough?

The disappointing answer: no. Even if PC owners * wipe their data from the hard drive with cleaning software, information can be left behind. “Both hard drive types have reserve areas in which data can be hidden,” explains Markus Häfele from the data recovery company I draw.

The formatting of hard drives, which is particularly popular with users, also offers not 100 percent Guarantee of deletion. Because here data could also remain in the reserve area if they were not overwritten. The expert advises: “Anyone who uses cleaning software or formats their hard drive should also ensure that all data is completely deleted.” A data recovery program such as Recuva can be used to easily check whether the hard drive has been properly cleaned.

Der Schredder as “Last Resort”

Complete deletion only guarantees physical destruction. “If you really want to be on the safe side, the only thing that helps is shredding,” says Häferle. But there is another option: those who think ahead can encrypt their hard drive before using their PC for the first time. With a so-called „Full Disk Encryption“ even with recovery programs it is not possible to access data in the reserve area.


  • If you want to completely erase your hard drive, you should definitely not on its operating system leaving. It is not enough to move files to the recycle bin or to empty it.
  • Find out if a classic magnetic hard disk (HDD) or one Solid State Disk is built into your PC. The deletion options differ from one another.
  • There are for both types of hard drives Cleaning-Softwares. When erasing HDDs, you can rely on the programs more when erasing SSDs. In any case, use data recovery software such as Recuva to check whether data is still hidden in the reserve area after the process.
  • Hard drives are 100 percent deleted only after their physical destruction. But if you think ahead, you can view your data before using your PC for the first time encrypt. So you are on the safe side.

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