How do I prepare my hard drive for resale?

When it comes time to sell or dispose of your old computer, you’ll want to make sure you properly wipe the hard drive to protect your personal information. Formatting or deleting files isn’t enough to prevent someone from recovering your data. To fully prepare your hard drive for resale or donation, you’ll need to completely overwrite the drive. Here’s a quick guide on how to securely wipe a hard drive before selling or recycling your computer.

Quick Answer: Use Drive Wiping Software

The easiest way to securely erase a hard drive is to use drive wiping software or disk utility programs. Options like DBAN (Darik’s Boot and Nuke), Active@ KillDisk, or Mac’s Disk Utility can completely overwrite all data on a drive. This overwriting process renders files unrecoverable and protects your personal information. Just boot the computer from the wiping software, select the drive to wipe, choose a wipe method, and let the program fully overwrite the drive.

Steps to Securely Wipe a Hard Drive

Follow these key steps to fully prepare your hard drive for resale or donation:

Back Up Important Data

Before wiping your hard drive, be sure to back up any important files or folders you want to keep. This could include documents, photos, music, browser bookmarks, and other personal data. Transfer these files to an external hard drive or cloud storage to preserve them through the wiping process. Fully wiping a drive erases everything, so back up what’s important first.

Delete Unneeded Files

Next, delete any files or programs on your computer that you no longer need. This helps speed up the drive wiping process. Empty the Recycle Bin and Trash to completely remove deleted files. You don’t need to keep any programs, applications, games, or temporary files. Removing them first simplifies wiping the drive.

Download Drive Wiping Software

There are many free and paid drive wiping tools available. Top options include:

  • DBAN (Darik’s Boot and Nuke) – Free open source data wipe tool
  • Active@ KillDisk – Paid wipe software with extra features
  • Mac Disk Utility – Free wiping option for Mac hard drives

Download and install your chosen wiping program. Make sure to pick the correct version for your computer’s operating system. These tools can wipe drives still installed in computers, as well as external drives.

Boot From the Wiping Tool

To fully wipe system drives, you’ll need to boot your computer from the wiping software instead of the installed operating system. This allows the tool to overwrite all drive partitions and sectors. Refer to the program’s instructions to create a bootable tool on CD/DVD or USB. Then, change your computer’s boot order to start from the wiping media, and boot it up.

Select the Drive to Wipe

Within the wiping program’s interface, you’ll select the drive you want to erase. Be very careful to choose the correct hard drive, as the wiping process is permanent. Double check you’ve chosen the proper drive before proceeding.

Choose a Wipe Method

Most tools offer different methods for overwriting drive data. A single pass write of all zeros is quick, but may be less secure. For maximum safety, choose a multiple pass method labeled something like “Gutmann Wipe” that overwrites data 35+ times. This takes much longer but ensures all old data is unrecoverable.

Start the Wiping Process

With your drive selected and wipe method chosen, start the data overwriting procedure. On a standard 500 GB hard drive, this may take 2-8 hours depending on the method. Don’t interrupt the process until it reaches 100% completion for full data removal. When finished, the drive contains no usable files or partitions. Shut down the computer, remove any wiping media, and the drive is now prepared for sale or disposal.

Extra Tips for Proper Hard Drive Wiping

Follow these additional tips to make sure you thoroughly wipe your hard drive before selling, donating or recycling a computer:

– For maximum security, use multiple wipe passes and advanced wipe methods like DoD 5220.22-M or Gutmann methods.

– Wipe SSDs safely using HDD erasure tools, but change settings to perform a secure trim/block erase for SSDs.

– Wipe each drive separately if wiping multiple drives.

– Check your computer BIOS and make sure drives are not set to RAID mode, which requires extra steps.

– Wipe external drives by connecting them directly to the computer booting the wiping software.

– On Macs, restart into macOS Recovery before wiping the primary system drive.

– Verify the drive wipe by scanning for residual data with a forensic tool after wiping is complete.

Answering Common Hard Drive Wiping Questions

Is drive wiping really necessary before selling or disposal?

Yes, drive wiping is highly recommended before selling, donating or recycling a used computer. Even deleting files or reformatting leaves recoverable data behind. Wiping fully removes sensitive documents, passwords, emails, internet history and other private information someone could otherwise retrieve from the sold drive. The small time investment helps protect your data.

Can’t I just delete everything or reformat the hard drive instead?

Simply deleting files or reformatting the drive does not reliably erase data. Deleted files can be recovered using free data recovery software. Reformatting only marks the existing data as deleted, but does not overwrite it. The only way to reliably prevent data being recovered from a used drive is to use proper drive wiping tools. These tools overwrite all drive sectors to make previous data unrecoverable by forensic analysis.

Is drive wiping safe for solid state drives (SSDs)?

Yes, you can safely wipe SSDs using HDD erasure tools. However, SSD storage cells work differently than traditional hard drives. Make sure to use a tool that performs a secure SSD trim or block erase instead of overwriting data. This sends an ATA command to the SSD firmware telling it to erase all cells. SSDs have spare cells and wear leveling that require this special wiping approach.

Can I wipe a hard drive that won’t boot?

If a hard drive is damaged and won’t boot into the operating system, you can still usually wipe it from an external booting tool like a USB or boot CD. Simply change the BIOS boot order to start from the external media, then run the drive wiping tool. As long as the drive is detected in the wiping software, it can be fully erased regardless of OS boot issues. Just be sure to select the correct non-booting drive to wipe.

Is overwriting a hard drive 7 times better than a 1 pass wipe?

It depends on your specific security needs. A single pass zero wipe is generally sufficient for consumer use, as it would require advanced forensic tools to recover any remnants of data. Government standards specify 3-7 wipe passes for maximum security when destroying highly sensitive data. Ultimately, even a single wipe pass on modern drives makes useful data recovery next to impossible. So 1 pass is good for home use, while 7 passes are recommended for truly sensitive data.

Prevent Recovering Deleted Files After Selling Drive

Be aware that in addition to your personal files, your hard drive contains privacy risks like internet history, log files showing online activity and cached passwords. Take time to fully wipe drives before allowing them to leave your possession. This prevents the next owner from gaining access to your private, sensitive data. Secure erase tools completely overwrite all drive sectors to render previous files and partitions unrecoverable. Follow these best practices of hard drive wiping to protect your information.


Preparing a used hard drive for sale or donation is an important step to secure your personal information. Simply deleting files or reformatting is not enough – you need to completely overwrite the drive using drive wiping software. This guide covered the necessary steps to securely erase your data using wiping tools like DBAN or Disk Utility. Be sure to fully wipe any drive before it changes hands. Taking this precaution helps safeguard your sensitive information from someone else accessing it in the future. With a thorough, complete overwriting of the entire drive, you can ensure your data is unrecoverable. Securely erasing hard drives before resale protects your privacy.