An external hard drive is a portable data storage device that can be attached to a computer via a USB connection or wirelessly. Reformatting an external hard drive erases all of the data and restores the drive to its original state. There are several reasons why you may want to reformat an external hard drive:
- To change the file system – For example, reformatting from FAT32 to NTFS to support larger file sizes.
- To permanently erase all data – Reformatting removes all files so they can’t be recovered.
- To resolve corruption or errors – Reformatting can fix problems with unreadable sectors.
- To reinstall the external drive for use with a different operating system.
Reformatting prepares the external hard drive to store new files. This guide will walk through the steps to safely reformat an external hard drive in Windows.
Reasons to Reformat an External Hard Drive
One key reason to reformat an external hard drive is to change the file system. The most common file systems for external hard drives are FAT32 and exFAT. FAT32 is compatible with older computers and devices, but can’t handle files larger than 4GB. exFAT allows much larger files but may not work with older devices.
If you are connecting your external drive to Windows and Mac computers, it’s best to format with exFAT. This allows large files while maintaining compatibility (https://www.oreilly.com/library/view/running-mac-os/9780596100605/ch04s03.html ). Reformatting the drive to exFAT enables this cross-platform compatibility.
You may also want to reformat to troubleshoot performance issues or errors with the drive. Reformatting completely rewrites the file system which can resolve underlying issues (https://superuser.com/questions/319595/are-there-any-performance-benefits-to-fully-formatting-a-hard-drive-vs-a-quick).
Back Up Your Data
Backing up your data is a crucial first step before reformatting an external hard drive. Reformatting will wipe all existing files and partitions on the drive, so you’ll lose everything if you don’t make backups.
To backup an external hard drive before reformatting, connect it and your backup drive to your computer. Then use backup software like UBackup or the built-in Windows Backup and Restore utility to copy all files and folders you want to keep.
Make two backup copies if possible, with one stored locally and one in the cloud or on another external drive. This provides redundancy in case one backup becomes corrupted or inaccessible.
Backup all personal files like documents, photos, videos, and music you want to keep. You may also want to backup program files and folders so you don’t have to reinstall software later.
Once your backup is complete, you can safely reformat the external hard drive knowing your data is stored securely elsewhere.
Connect the External Hard Drive
Connecting the external hard drive to your computer is the first step in reformatting it. Here are the steps to properly connect an external hard drive:
First, plug the external hard drive’s USB cable into an available USB port on your computer. USB 3.0 connections only fit one way, while USB-C connections are reversible. If you have a USB-C hard drive, check that the connectors are aligned properly before plugging in.
Once the cable is securely plugged into the computer, plug the other end into the external hard drive. The drive may have a USB port, or the cable may plug directly into the drive enclosure.
Turn on the external drive if it has a separate power switch. The drive should instantly mount and appear on your desktop on Mac or in File Explorer on Windows.
If the drive does not appear, try unplugging both ends of the cable, waiting a few moments, and plugging it back in. You can also try plugging the cable into a different USB port on your computer.
For more information, refer to the external guides here:
[1] How to Easily Add an External Hard Drive to a Mac or PC
[2] External Hard Drive Setup and Formatting
Check Drive Status in Disk Management
The next step is to check if Windows recognizes the drive in Disk Management. Disk Management is a built-in Windows tool that allows you to manage internal and external drives connected to your computer.
To open Disk Management on Windows 10 or 11:
- Type “Disk Management” in the Windows search box and click on the “Create and format hard disk partitions” result.
- You can also right-click on the Start menu and select “Disk Management”.
On Windows 7:
- Go to Start > Control Panel > Administrative Tools > Computer Management > Storage > Disk Management.
In Disk Management, check if your external drive shows up in the list of available disks on the lower half of the screen. If you see the drive but it says “Unallocated” or “Not Initialized”, Windows recognizes the drive but you need to initialize it before use.
If the external drive is not showing up at all in Disk Management, Windows is unable to detect the drive for some reason. This could be caused by a damaged cable, power issue, partition issues, or other factors. Troubleshooting tips can be found at this Microsoft support article.
Initialize the Drive
After connecting the external hard drive and checking its status in Disk Management, the next step is to initialize it. Initializing the drive prepares it for use by erasing all previous data and partitioning information. This is an important step before the drive can be formatted and assigned a drive letter.
To initialize the drive, right-click on the disk name and select “Initialize Disk” from the context menu. You will be given the choice to initialize the disk as MBR (Master Boot Record) or GPT (GUID Partition Table).
For most home users, choosing MBR is recommended, as it is compatible with older and newer versions of Windows. GPT is required for drives larger than 2TB and for certain advanced partition configurations, but is not as widely compatible.
After selecting MBR or GPT, the initialize operation will run. All existing data on the drive will be erased. Once complete, the disk will show as “Unallocated” space, ready to be formatted with a new volume.
Initializing the disk to an MBR or GPT layout is a critical first step when reformatting an unrecognized external drive. This erases any previous formatting issues and allows new partitions and volumes to be created.
Create a New Simple Volume
Once the drive is initialized, the next step is to create a new simple volume on the unallocated space. This can be done using the New Simple Volume Wizard in Disk Management. The wizard will walk you through the steps to create a volume with the desired size and file system https://www.easeus.com/partition-manager-software/new-simple-volume.html.
To launch the wizard, right-click the unallocated space and select “New Simple Volume” from the menu. In the first step, specify the size of the volume in MB. It’s best to allocate the maximum available space unless you need multiple volumes. The wizard will automatically assign the next available drive letter or you can choose your preferred letter.
Next, select the file system – NTFS is recommended for compatibility and security. The wizard will perform a quick format to create the blank NTFS volume. Once completed, the new volume will appear in File Explorer ready to use. The simple volume behaves like a separate drive so you can access and manage files as you would on any internal or external drive.
Format the Volume
After the new simple volume has been created, the next step is to format it. Formatting will erase all data on the drive and prepare it for use with your operating system.
To format the volume, right-click on it in Disk Management and select “Format…” [1]. This will open the format dialog box.
The default and recommended file system option is NTFS (NT File System). NTFS is the standard system for Windows and has improved features for performance, security and reliability compared to the older FAT32 system. Unless you specifically need FAT32 for compatibility reasons, you should format to NTFS.
You can also choose the allocation unit size, which determines the size of the clusters on the drive. The default selection is fine for most uses. Make sure to check “Perform a quick format” to format the drive faster.
When ready, click “OK” to begin formatting the volume. Once completed, the volume will be ready to store files and data.
Assign a Drive Letter
In order for Windows to recognize and access the external hard drive, you need to assign it a drive letter. Without a drive letter, the external hard drive will not show up in Windows File Explorer even though it is connected.
To assign a drive letter:
- Open Disk Management.
- Right-click the external hard drive’s partition or volume and select “Change Drive Letter and Paths.”
- Click “Add.”
- Select a drive letter from the drop-down menu that is not already in use. An unused letter like Z or Y works well.
- Click “OK.”
The external hard drive will now be accessible in File Explorer with the new drive letter.
If the drive does not show up even after assigning a letter, you may need to restart your computer and check Disk Management again before the drive will appear.
Reference: https://www.startech.com/en-us/faq/hard-drives-general-assign-change-drive-letter
Safely Remove External Drive
After reformatting your external hard drive, it’s important to properly eject the drive before physically removing it or powering it down. This prevents potential data loss or corruption by ensuring any cached writes are flushed from the computer’s memory to the drive.
On Windows, locate the external drive icon in File Explorer and right-click it. Select “Eject” from the menu. An icon appears in the system tray indicating it’s safe to detach the hardware. On Macs, click the eject button next to the drive name in the Finder sidebar or drag the icon from the desktop to the Trash. Ejecting the drive properly before removal is important to avoid potential file system or data corruption.
For laptop users, simply unplugging an external drive without ejecting can potentially lead to data loss or file system damage. Always eject external drives before powering down or putting a laptop to sleep as well. Failing to properly eject can sometimes lead to the drive not being recognized next time it’s plugged in, requiring reformatting again.
