How to reformat hard drive?

Reformatting or repartitioning a hard drive is the process of erasing all data on the drive and setting up a new file system. This can be useful if you want to completely wipe a drive before selling or giving away a computer, if you want to change the file system type, or if you are having issues with a corrupted drive. Reformatting a drive will erase all data on the drive, so be sure to backup anything you want to keep beforehand.

When Should You Reformat a Hard Drive?

There are a few common situations when reformatting a hard drive may be necessary:

  • You are selling or giving away your computer and want to wipe the hard drive.
  • You are switching from Windows to Mac or vice versa and need to change to the appropriate file system.
  • You want to change the file system type (for example, from FAT32 to NTFS).
  • Your hard drive is corrupted or has bad sectors and you want to do a low-level reformat.
  • You have a new hard drive you want to use and need to set up a file system.

Reformatting cleans the slate and allows you to reuse a hard drive. Just be aware that it will erase all data, so back up what you need to keep first.

How to Back Up Your Data

Before reformatting, be sure to back up any data and files you want to keep. There are a few options for backing up your data:

  • External hard drive: Copy important files to an external USB hard drive.
  • Cloud storage: Upload files to a cloud storage service like Dropbox, Google Drive, or Microsoft OneDrive.
  • Network storage: If you have a home server or network attached storage (NAS), copy important files there.
  • Online backup service: Use a service like Backblaze or Carbonite to back up your files.
  • USB flash drive: You can copy smaller amounts of data to a USB flash drive.

Be sure you have backups of any data you need before proceeding with reformatting the drive. Reformatting will erase everything.

How to Reformat a Hard Drive on Windows

Here are the steps to reformat a hard drive on a Windows PC:

  1. Open the Start menu and type “Disk Management.” Select Create and format hard disk partitions.
  2. Right-click on the drive you want to reformat and choose Format.
  3. Select the file system you want. NTFS is recommended for Windows. FAT32 has some limitations but may be necessary for older systems.
  4. Give the drive a volume label if you want and make sure Quick Format is checked.
  5. Click OK to begin formatting the drive. This will erase all data.
  6. Formatting will take a little while to complete. When done, the drive will show the new file system and capacity.

The steps are very similar if you want to reformat a USB flash drive or external hard drive on Windows. Just right-click it in Disk Management and choose Format.

Some key things to note about reformatting on Windows:

  • Make sure you select the correct hard drive to avoid erasing data from the wrong drive.
  • NTFS is the standard Windows file system. Use FAT32 only if the drive needs to be compatible with older OS versions.
  • Quick format is faster but a full format will scan for bad sectors. Use the latter if you suspect drive issues.

That covers the basics of reformatting a drive on a Windows PC. Just go slow, confirm the right drive is selected, and backup your data first.

How to Reformat a Hard Drive on Mac

To reformat a hard drive on Mac:

  1. Open Disk Utility (located in Applications > Utilities).
  2. Select the hard drive you want to reformat in the sidebar.
  3. Click Erase at the top of the Disk Utility window.
  4. Choose a format for the drive. APFS is standard for macOS. MS-DOS (FAT) is useful for external drives to use with Mac and Windows.
  5. Give the drive a name and click Erase to reformat it. This will delete all data.

As with Windows, make absolutely certain you have backups before erasing the drive. Double and triple check you have the correct drive selected before erasing.

Some tips for reformatting on Mac:

  • Use APFS for macOS internal drives and HFS+ for older versions.
  • MS-DOS (FAT) format allows external drives to be used by both Mac and Windows.
  • Encrypted and secure erase options can be used for more security when wiping a drive.
  • partitioning tools in Disk Utility allow you to split the drive into multiple volumes.

Follow those steps, be cautious in selecting the correct drive, and have backups – and you should be able to safely reformat your Mac hard drive.

How to Do a Quick or Full Format on Windows

When reformatting a drive on Windows, you have the choice of a quick format or full format:

  • Quick Format: This is faster, but only marks the existing disk space as available. It does not scan for bad sectors.
  • Full Format: Takes longer, but scans every sector for defects. Use this if you suspect issues with the hard drive.

To choose between quick and full format in Windows:

  1. Open Disk Management, right-click the drive, and choose Format.
  2. In the Format window, deselect Quick Format to perform a full format.
  3. Select Quick Format if you want the faster option instead. This is the default.
  4. Click OK to begin formatting using your choice of quick or full format.

When should you use quick vs full format?

  • Use Quick Format if you are in a hurry and the drive is new or known to be in good health.
  • Use Full Format if the drive is showing errors, has bad sectors, or you suspect problems.
  • Use Full Format if you are selling the PC and want to completely wipe data.

The full format takes much longer but is more thorough in checking for drive issues. Use it selectively when you suspect drive problems or want to do more complete data wiping.

Tips for Reformatting an Old Hard Drive

Trying to reformat an older hard drive? Here are some tips:

  • Defragment the drive first if it is noticeably slow. This can speed up the reformat.
  • Use the full format option to scan for bad sectors.
  • Consider zero-filling the drive with diskpart clean command to completely wipe data.
  • Check S.M.A.R.T. drive errors in Disk Utility before reformatting.
  • Monitor drive temperature during formatting – high temps can indicate issues.
  • Consider replacing the drive if problems persist after reformatting.

Reformatting can help improve performance on an older drive. But if the hard drive is malfunctioning, it may need to be replaced.

Watch for warning signs like overheating or excessive bad sectors. It may be time for an upgrade if the drive is showing its age. Reformatting should help, but won’t fix a failing drive.

Can You Reformat an External Hard Drive?

Yes, reformatting external hard drives uses the same process as internal drives. Just connect the external drive, then use Disk Management in Windows or Disk Utility on a Mac to erase and reformat the external drive.

Some tips when reformatting an external drive:

  • Use the native utility in the OS to avoid issues – don’t try to reformat with a third-party tool.
  • Make sure to select the correct drive so you don’t accidentally erase your computer’s main drive.
  • FAT32 format can be helpful for external drives since it works on both Windows and Mac.
  • Large external drives may have extra partitions, so make sure to select the main drive partition itself to reformat.

The steps are otherwise the same. Backup data, connect the drive, use Disk Management or Disk Utility, select the correct drive, choose format, and erase.

Just take care to identify the correct external drive before erasing to avoid accidentally wiping your computer’s main hard drive.

Should You Delete or Format a Hard Drive?

When getting rid of an old computer, you have two options for wiping the hard drive – formatting or deletion:

  • Format: Completely erases all files and rewrites the file system. More secure erase.
  • Delete: Removes references to files in file system. Files can be recovered. Less secure.

For privacy and security when disposing of a drive, formatting is better than just deleting files:

  1. Deleted files can be recovered with recovery tools.
  2. Formatting completely overwrites file system and erases data.
  3. Quick format is fast but leaves some recoverable data. Use full format for more security.
  4. On SSDs, encryption is required to fully erase all data remnants.

So for maximum security when getting rid of a drive, use the format option instead of just deleting files. And for SSDs, use drive encryption first before formatting for best results.

What is a Low-Level Format?

A low-level format completely erases and retests every sector on a hard drive:

  • Writes zeros or other patterns to the entire drive surface to wipe all data.
  • Checks the magnetic properties of drive platters to map out bad sectors.
  • Used to be necessary preparation for hard drive use, now rarely needed.
  • Should not be confused with standard quick or full formatting, which only erases file system.

Reasons you may need to low-level format a drive:

  1. Diagnosing and mapping out bad sectors.
  2. Erasing data prior to drive disposal.
  3. Removing malware or viruses from the deep disk areas.
  4. Preparing damaged drives for recovery tools.
  5. Very old disks may require it prior to use (rare today).

Low-level formatting is not normally needed for drive repurposing. Standard formatting is typically sufficient. But it remains a tool for drive diagnostics and deep erasure.

How to Securely Wipe a Hard Drive

To securely wipe a hard drive prior to disposal or donation, use these methods:

On Windows:

  • Use the full format option, not quick format, when reformatting.
  • Use diskpart’s clean command with zeros option to overwrite data.
  • Use a wipe utility like Darik’s Boot and Nuke (DBAN).
  • Encryption first provides added protection on SSDs and flash media.

On Mac:

  • Choose secure erase option when reformatting in Disk Utility.
  • Use diskutil secureErase command with zeros to overwrite.
  • Use a dedicated wipe tool like WipeDrive to clearly erase.
  • FileVault 2 encryption should be enabled before wiping SSDs.

For safe data disposal, don’t just delete files – make sure to use encryption and wiping software to completely overwrite sensitive information. This will deter typical recovery attempts.

What Happens When You Reformat a Hard Drive?

Here’s an overview of what happens when you reformat a hard drive:

  1. Warning prompts: You’ll get prompts to back up data and confirm drive erasure.
  2. Partition removal: The existing partitions and data are deleted.
  3. File system creation: A new blank file system is written (NTFS, FAT32, etc).
  4. Drive formatting: The basic structure of sectors and tracks is created.
  5. Checks for defects: With full format, the drive is scanned for bad sectors.
  6. Accessibility reset: The reformatted drive is now ready for new data to be stored.

Reformatting resets the drive back to a clean slate state for reuse. Carefully go through the proper steps for your operating system to avoid mishaps.

And remember – always have your important data backed up before reformatting any drive to avoid catastrophic data loss!

Recap of Best Practices

Here’s a quick recap of best practices when reformatting a hard drive:

  • Backup your data – All data will be erased, so copy important files elsewhere first.
  • Use the right tools – Use native OS tools like Disk Management or Disk Utility.
  • Select the correct drive – Double and triple check you have the right drive selected.
  • Choose the file system – NTFS for Windows, APFS for Mac, FAT32 for portability.
  • Quick vs full format – Quick for fast erasure, full for bad sector checks.
  • Securely wipe when necessary – Use wipe tools like DBAN for safe drive disposal.

Follow these tips and reformatting your hard drive can be a smooth, hassle-free process. Just go slow and be extra cautious when erasing.


Reformatting a hard drive is a straightforward process – just be sure to backup data, use the proper steps for your OS, and be extremely careful when selecting the drive to erase. Always keep your irreplaceable files copied elsewhere before a reformat.

With drive formatting built into Windows, Mac, and Linux, it’s a basic maintenance task that nearly any user can perform. But rushing through and making a mistake can lead to permanent data loss. So pay close attention, read the warnings, and double check the right drive is targeted.

Follow the guide above and reformatting will go smoothly. But if in doubt, find an experienced technical friend who can check over your work before pulling the trigger and wiping your drive. An extra set of eyes could save you from disaster.

Just remember – once that reformat starts, the data is as good as gone. So have backups and be cautious when picking the disk to erase. With the proper precautions, you’ll have the process mastered in no time.