How do I completely delete files from my computer?

by
How do I completely delete files from my computer

Completely deleting files from your computer is an important step to protect your privacy and free up storage space. When you delete a file normally, it simply removes the reference to that file from your operating system. The actual data is still on your hard drive and can be recovered with the right tools. To prevent this, you need to securely and permanently erase files. Here are some quick answers about completely deleting files:

How is normal file deletion different from permanent deletion?

When you delete a file normally through your operating system, it simply marks the space that file took up as being available for new data. The actual contents of the file remain on your hard drive until that space is overwritten by new files. This means the file can be recovered using data recovery software.

Permanently deleting a file overwrites the data in that part of the hard drive to make it unrecoverable. The file is not simply marked as deleted, but actually replaced with random data to make recovering it impossible.

Why should I permanently delete files?

Here are some reasons you may want to permanently delete files:

  • Privacy – Delete personal files you don’t want others accessing from your computer if lost or stolen.
  • Security – Delete files that may contain sensitive information like financial records and account numbers.
  • Free up space – Overwritten files can no longer take up valuable storage capacity.
  • Prevent recovery – Delete files so they are unrecoverable by data recovery software.

When should I permanently delete files?

Some common situations when you should permanently delete files include:

  • Before selling or donating your computer – Wipe personal files first.
  • Before allowing repairs – Delete private files so repair techs won’t see them.
  • After a data breach – Prevent stolen files from being accessed if hacked.
  • When deleting financial records – overwrite tax returns and bank statements.
  • Before deleting sensitive photos – Remove exif data and overwrite originals.

How can I permanently delete files on Windows?

Here are some ways to permanently delete files on Windows computers:

  • Use Eraser – This free software overwrites files making them unrecoverable.
  • Wipe Free Space – Tools like CCleaner can wipe deleted file space.
  • Use File Shredder – Shred files and make them unrecoverable.
  • Delete from Command Prompt – The “cipher” command can wipe files.
  • Turn on Trim – Enables SSD drives to instantly wipe deleted blocks.

Using Eraser

Eraser is a free program designed to completely remove sensitive files on Windows. To use it:

  1. Download and install Eraser from their official website.
  2. Right-click the file or folder you want to permanently delete and select “Erase with Eraser”.
  3. Choose a secure deletion method like the Gutmann method.
  4. Click “Erase Now” to permanently overwrite and delete the file.

Wiping Free Space

To prevent recovery of deleted files on your hard drive, you can wipe the free space that may contain remnants of old files. CCleaner has a Drive Wiper tool that can perform this task:

  1. Download CCleaner and install the free version.
  2. Open CCleaner and click the “Tools” icon.
  3. Select “Drive Wiper” and choose a drive to wipe.
  4. Click “Wipe Free Space” to overwrite the empty space on the drive.

Using File Shredders

File shredding programs are designed to completely remove files by overwriting them multiple times. Popular options include:

  • SDelete – Free secure delete tool from Microsoft.
  • Hardwipe – Freeware file shredder for home use.
  • ShredIt – Basic software for shredding files and disks.

To use a file shredder, simply right-click the file you want to shred and select the shred option from the menu.

How can I permanently delete files on Mac?

MacOS offers a couple ways to securely erase files:

  • Secure Empty Trash – Empties the trash by overwriting files.
  • Disk Utility – Wipes entire disks or partitions.
  • Terminal – Access secue delete commands like “srm”.

Secure Empty Trash

To use Secure Empty Trash to permanently delete files on Mac:

  1. Move files you want to delete to the Trash.
  2. Open the Finder menu and select “Secure Empty Trash”.
  3. Select the “Securely remove items by overwriting” option.
  4. Click “Empty Trash” to overwrite and delete files.

Using Disk Utility

MacOS Disk Utility can wipe full drives and partitions. To use it:

  1. Open Disk Utility.
  2. Select a drive or partition.
  3. Click the “Erase” button.
  4. Choose a secure erase option like “Most Secure”.
  5. Click “Erase” to wipe the drive.

Deleting from Terminal

You can access advanced secure delete commands using the MacOS Terminal app, such as:

  • srm – Securely removes files by overwriting data.
  • sfill – Fills free space on a drive with junk data.
  • nwipe – Securely wipes drives using different methods.

How can I wipe an SSD drive?

Solid-state drives (SSDs) store data differently than traditional hard disk drives (HDDs). However, you can still securely wipe data from an SSD using these methods:

  • Use ATA Secure Erase – This command wipes all data from an SSD.
  • Use PartedMagic – Boot into this OS and wipe SSDs.
  • Encrypt before erasing – Enable encryption like BitLocker before performing a standard deletion.

ATA Secure Erase

ATA Secure Erase is a built-in command supported by most modern SSDs that performs a complete data wipe. To use it:

  1. Backup data and power off computer.
  2. Boot into BIOS and enable ATA Secure Erase.
  3. Boot back into BIOS and run the Secure Erase command.
  4. Reboot once complete and the SSD is wiped.

Using PartedMagic

PartedMagic is a lightweight operating system designed to wipe drives. To use it to erase an SSD:

  1. Download PartedMagic ISO.
  2. Create bootable media like a CD or USB drive.
  3. Boot computer from the media.
  4. Choose “SSD Erase” option and select the SSD.
  5. Reboot computer when complete.

Can data recovery software retrieve permanently deleted files?

If you overwrite a file using a secure deletion technique, data recovery software cannot retrieve it. Here is some more detail:

  • Overwriting deletes data permanently – There is no way to retrieve an overwritten file.
  • Multiple passes are most secure – The more overwrites, the better.
  • Data may remain in slack space – Small remnants may escape a quick wipe.
  • Encrypting helps prevent recovery – Encrypt files before deletion for security.
  • Physical destruction is foolproof – But only as a last resort.

While no method is 100% foolproof, using a tool designed to securely overwrite files and wiping free space on a drive will prevent all but the most sophisticated attacks from recovering deleted data.

How do I securely wipe external storage devices?

To permanently delete data from external devices like USB drives, SD cards and external hard drives, use these steps:

  1. Backup any data you want to keep elsewhere first.
  2. Use disk utility tools to perform a full drive wipe.
  3. Or create a bootable live OS like PartedMagic for drive erasing.
  4. Booting into BIOS and using ATA Secure Erase also works if supported.
  5. For flash drives, use shredder tools or the SD Association’s Toolbox.

The same principles apply as wiping an internal drive, just performed through an external interface like USB or Thunderbolt. Be aware that flash memory in thumb drives can relegate some data to inaccessible areas, so combine several wiping techniques for best results.

What tools do professionals use to permanently wipe drives?

IT professionals often use enterprise-grade disk sanitation tools to permanently and securely erase data from storage devices. Some examples include:

  • Blancco – High-end drive erasure used by corporations and governments.
  • Active@ KillDisk – Comprehensive data wipe out for HDDs and SSDs.
  • R-Studio Disk Eraser – Uses various wiping patterns for logical drive erasure.
  • Disk Wipe – Securely cleans disks to Department of Defense standards.
  • WipeDrive – Enterprise HDD erasure for desktops and servers.

These tools fully overwrite all data at a disk level, meeting verification standards like DoD 5220.22-M for safe and permanent data destruction.

Can I recover a permanently deleted file?

If a file has been completely overwritten even just once, it is likely unrecoverable through software alone. However, there are a couple very expensive options that may work in some cases:

  • Use a data recovery service – But results aren’t guaranteed.
  • Reconstruct data from the disk platters – An expensive forensic technique.
  • Repair the storage device – Specialists can work magic sometimes.
  • Piece together remnants from slack space – Partial files may be recoverable.

But these options are rare occurrences and can cost thousands of dollars. So for any normal user, a securely overwritten file is essentially unrecoverable through conventional means. The best way to recover deleted files is always from a backup.

Conclusion

Permanently deleting files requires overwriting the data to prevent any chance of recovery. Free tools like Eraser and CCleaner provide an easy way to securely remove files on Windows. MacOS offers options like Secure Empty Trash and Disk Utility. For external devices, wipe tools and bootable OSes get the job done. While an overwritten file is essentially unrecoverable through software alone, backups provide the only sure way to recover deleted files. Following best practices for securely wiping your digital data can help minimize the risk of unwanted recovery.