This is how you really empty your PC

A traditional hard drive consists of one or more platters: round discs that look like thick CDs. The plate is a piece of glass or aluminum covered with a metal layer. Hard drives with little storage have one platter, larger drives have two or more platters. Each plate contains thousands of sectors that can be filled with data. As more is written to the disk and the files are removed from the disk, gaps are created that can later be filled with parts of the new files. A hard drive can clean these holes right away, this is called defragmentation. This is the process of moving datasets of the same file so that they are no longer scattered across the disk surface and are kept in composite sets. Such an operation obviously requires a large number of writes, and that’s not exactly what SSDs were made for. Therefore, defragmentation comes at the expense of speed.

A common misconception is that formatting a hard drive means erasing all existing data so that the drive can be used again. In fact, not all sectors were cleared. Only references to files are removed. Basically, you are telling the hard disk that all existing sectors can be considered free space and new files can be written to all sectors on the disk. The more you do with the drive, the more old files disappear as they make room for new files. But if you want to sell the disk PC, you need to delete your data properly. Therefore, simply formatting and reinstalling Windows is not enough. Then, of course, all your settings will be deleted, but some data can be easily recovered with recovery software.

In another article, we give 9 tips to keep your disk healthy. We explain how to test the reliability of your drive, how to keep it clean and how to defragment it.

Therefore, if you want to sell a disk, you must make sure that your sectors are overwritten with new, useless information. This is exactly what happens with a ‘comprehensive format’. The program you use for this will rewrite your hard drive several times with random data or a pattern of ones and zeros. The more often you do this during formatting, the more confident you can be that the files won’t be found.

There are several levels where the Gutmann method is the most complex. A disc is overwritten 35 times with different algorithms per overwrite. This system is too verbose for most applications, so there are lighter overwrites. The US defense uses a seven-way transfer method by default, but a two- or three-way transfer should suffice for home, garden and kitchen use. You can use the well-known CCleaner software for Windows. If you are not using this program yet, click here Download Free Version and still struggle between pages asking you to download a paid version. Click on it once installed Tools / Driver Wiper and check the name of the drive you want to format.

make sure you have your back sweep away choice Entire Drive (all data will be erased) we chose. back Security then determine how often the disc should be overwritten with random data. Advanced Overwrite (3 passes) it is really sufficient for most applications and almost guarantees that no data recovery is possible. Choice Complex Overwrite (7 passes) recommended for defense hard drives and overkill for the standard user. last option Very Complex Overwrite (35 passes) it only makes sense if you have access to warheads and have a lot of time, as this can take several days. click sweep away to start the process.

On Mac, secure disk formatting is included in macOS by default. Open Programs / Utilities and start Disk Utility. Select the external drive you want to format and delete. click Security options and select the security level. You have four options, the safest method (correct option) is to overwrite the data seven times. If you want to format an internal drive, the security options will not appear.

An SSD works differently from a regular hard drive and its lifespan is highly dependent on the number of read and write cycles. If you completely overwrite the disk several times using a program like CCleaner, you will immediately shorten the life of your SSD. To completely erase data on an SSD, you need to perform an operation called ATA Secure Erase. This causes a short voltage spike to the SSD that resets all sectors to their initial state. It’s as if the SSD has been short-circuited and its memory has been permanently wiped. To issue such an ATA Secure Erase, you need to look for a special tool on your SSD manufacturer’s website. For Samsung, for example, this is the Samsung Magician software.

Another option is to encrypt your entire SSD drive before formatting. Then format the SSD from another computer and encrypt the SSD again. This will overwrite your initial encryption, which is normally stored on the SSD itself. In this way, your old data is no longer accessible. Encryption is done via BitLocker on Windows 10 Pro and Enterprise, you can find it at: Control Panel / System and Security. For example, in other versions of Windows you would use the free VeraCrypt tool. This freeware was released years ago as the open-source successor to the mysteriously disappeared Truecrypt. In all these years, nothing has really changed in the way it works, but if you have never used the tool, you can read about how to encrypt disks, as well as files and folders in another article.

You can find FileVault on macOS at: Settings / Security & Privacy. click the tab file vault and then click the padlock to enter an administrator name and password. click Change FileVault inside.

You cannot format a boot disk from your own operating system, so you must remove your hard disk from the PC and place it in an external slot to format it. Another option is to create the recovery media of your Windows system and then boot from your computer with that media. Now that you are running your operating system from other media, you can format your C drive like an external drive.