How do you erase an old computer

Securely delete all data before selling a PC

Friedrich Stiemer

If you want to sell your PC or laptop, you of course delete all data that is still on the device in advance. Windows 10 also has a function ready for this. But is that really enough to prevent your files from recovering? We clarify.

EnlargeSecurely delete all data before selling a PC

Microsoft has given its Windows 10 operating system two options that should make it easier to give away a PC. You can find it in the settings, which you open with the Windows-I key combination. Please click there on the entry "Update and Security". On the left side then select "Restore" and in the right half of the window under the item "Reset this PC" then the option "Let's go". In the following window select "Remove all". Windows advises you that this setting will only remove files: "This is faster, but less secure". If you only want to reset the computer and continue using it yourself, you can leave it that way. However, if the system is to be transferred to someone else, click on “Change settings” and now switch on “Data erasure”, which completely cleans up the unused space on the hard drives, can take several hours and makes it much more difficult to restore data. You can start by clicking on "Confirm". Both options reset Windows 10 to the delivery state, a reinstallation of the operating system is not necessary.

EnlargeWindows 10 already offers the option of shredding unused storage space ex works to make data recovery more difficult.

If you have accidentally selected the first and faster option, although you actually want to give up the PC, you do not need to carry out the data deletion again. Instead, you can have the unused storage space overwritten later to make recovery more difficult. You do this using the command prompt. Call it up as administrator by typing command prompt in the Windows search field and then clicking on the command “Run as administrator”. The command for safely overwriting (or "shredding") unused memory is cipher / w: c :. In this case, the entire unused memory of the C drive would be shredded - replace the letter with the letter of the drive you want. This command proceeds as follows to make data recovery more difficult: First, the free space is overwritten with zeros, then with ones, in order to be filled again with random data in the next step. Depending on the size and speed of the storage medium, overwriting can therefore take several hours.

EnlargeOnly a Secure Erase of SSDs reliably overwrites the flash memory. The corresponding deletion tools are available from the manufacturers or from third-party providers.

Strictly speaking, however, this method is only 99.99 percent secure - theoretically, there is still the possibility that the data can be restored. But rest assured: this requires a lot of effort and investment. If you want even more security, you should carry out a so-called Secure Erase for SSDs and format and overwrite HDDs completely. The Windows option with data deletion should generally be sufficient for home use.

Tip:Erase safely - the top tools from PC-WELT readers