Reformat External Hard Drive on Windows or Mac Without Losing Data

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Reformatting an external hard drive can resolve performance issues, fix file system errors, or simply prepare it for use with a different operating system. However, the process usually comes with one major concern: data loss. Many users hesitate to proceed with formatting because it typically erases everything on the drive. Fortunately, there's a safe way to reformat your external hard drive on Windows or Mac without losing data - and this guide will walk you through it step-by-step.

Can You Reformat Without Losing Data?

Let's clarify this upfront: reformatting a drive will delete all data stored on it. However, this doesn't mean you're doomed to lose your files. The key to preserving your data lies in backing it up beforehand and restoring it afterward.

In essence, the process involves three core steps:

1. Backup your files to another safe location.
2. Reformat the external drive using Windows or Mac utilities.
3. Restore your files back onto the freshly formatted drive.

If you forgot to back up your files and had formatted the external hard drive, data loss is certain and inevitable. At this point, you'd better perform data recovery as soon as possible to avoid permanent data loss.

How to Reformat an External Hard Drive Without Losing Data?

By following these steps, you ensure that your data remains intact throughout the reformatting process.

Step 1: Back Up the Data from Your External Hard Drive

Before making any changes to your external hard drive, backup is crucial. Skipping this step could lead to permanent data loss.

Option 1: Manual Copy

• Connect your external hard drive to your PC.
• Open File Explorer (Windows) or Finder (Mac).
• Select all files and folders.
• Copy them to:
  • Another external drive
  • Your internal hard drive (if space allows)
  • A cloud storage solution

Option 2: Use Backup Software

If your data is large or you want automation:

• Windows: Use File History or third-party tools like Donemax Disk Clone, True Image.
• Mac: Use Time Machine to back up to another external drive.

Step 2: Choose the Right File System Format

When you format a drive, you'll be prompted to choose a file system. The format you choose determines compatibility, performance, and features like file size limits or encryption.

Recommendation:

• Choose exFAT if you plan to use the drive on both Windows and Mac.
• Choose NTFS if you only use Windows and need features like file compression or encryption.
• Choose APFS or Mac OS Extended if the drive is strictly for use with Mac systems.

Step 3: Reformat the External Hard Drive on Windows

Here's how to reformat your external hard drive safely on Windows 11, 10, 8, or 7:

Step-by-Step Guide:

1. Connect the external hard drive to your PC.
2. Press Windows + X and select Disk Management.

3. Locate your external drive in the list.

4. Right-click on the drive's partition and choose Format.

5. In the dialog box:
   • Enter a volume label (drive name).
   • Choose File System (e.g., exFAT, NTFS).
   • Select Default for Allocation Unit Size.
   • Uncheck "Perform a quick format" for a deeper clean (optional).

6. Click OK and confirm the warning about data loss.

Alternative: Using File Explorer

1. Open File Explorer and right-click the drive.
2. Click Format.

3. Select the desired options and click Start.

💡 Note: The Disk Management method gives more control, especially if you need to delete and recreate partitions.

Step 4: Reformat the External Hard Drive on Mac

If you're using a Mac, here's how to reformat your external hard drive:

Step-by-Step Guide:

1. Attach your Mac to the drive.
2. Open Disk Utility: Go to Applications > Utilities > Disk Utility, open Disk Utility.

3. In the left sidebar, select your external hard drive (not the volume).

4. Click the Erase button at the top.

5. In the popup:
   • Name your drive.
   • Choose a format (e.g., APFS, exFAT, Mac OS Extended).
   • Choose GUID Partition Map as the scheme.
6. Click Erase to begin formatting.

💡 Note: Erase will delete all content, so make sure your backup is safe.

Step 5: Restore Your Files to the Reformatted Drive

Once you've successfully reformatted your external hard drive, the final and most rewarding step is to put your data back where it belongs. Whether you're restoring from a manual backup or a full system image, this stage is where you bring your drive back to life - without any of the old problems and clutter that may have prompted you to format it in the first place.

1. Manual Restoration (File-by-File)

This is the most straightforward method, especially if you backed up your files manually.

How to Do It:

1. Locate Your Backup: This could be another external drive, a specific folder on your internal disk, or even a cloud storage location.
2. Connect or Open the Backup: If it's another physical drive, plug it in. If it's in the cloud, make sure you're signed in and synced.
3. Drag and Drop: Simply select the backed-up files and folders and copy them to the freshly formatted external hard drive.
4. Preserve Structure: If you had a specific folder structure (e.g., Documents, Media, Projects), recreate that same hierarchy to stay organized.
5. Verify the Data: Open a few documents, media files, and folders to make sure everything has been restored correctly and is accessible.

Example:

Imagine your original external drive had a project folder for a client that contained designs, invoices, and meeting notes. After restoring, open some of these files to ensure they are intact and that formatting (in Word, Excel, or design tools) hasn't been lost or corrupted in the process.

2. Using Backup Software for Restoration

If you used dedicated backup software like Time Machine, Acronis True Image, you can restore your files even more efficiently, with options like version control and partial recovery.

Time Machine on macOS:

• Reconnect your Time Machine backup drive.
• Open Time Machine from the menu bar or System Settings.
• Browse through snapshots of your system to locate files.
• Click Restore to send them back to the newly formatted external drive.

Acronis (Windows):

• Launch the software and go to the Restore tab.
• Choose the appropriate backup image file.
• Select specific files/folders or restore the entire backup.
• Set the destination to your reformatted external drive.
• Click Proceed and monitor the process.

Advantages:

• Recovers all metadata (timestamps, permissions, etc.).
• Supports restoring specific versions of files.
• Often faster and more automated than manual copying.

3. Cloud Backup Restoration

If you uploaded your backup to services like Google Drive, OneDrive, Dropbox, or iCloud, you can restore directly from the cloud.

Steps:

• Sign in to your cloud account.
• Navigate to your backup folder.
• Select all files and click Download or drag them to the external hard drive.
• Make sure the internet connection is stable, especially when transferring large files.

Pro Tips:

• Use a download manager to avoid interruption.
• Verify available space on the external drive before initiating a large transfer.
• Be patient - cloud downloads can take time depending on your internet speed.

Organizing the Restored Data

After restoration, it's worth spending a few minutes to organize your drive for better long-term usability:

• Create category-based folders: e.g., Work, Personal, Media, Archives.
• Use naming conventions: "Invoices_2025_ClientName" is clearer than "File1.docx".
• Remove duplicate or obsolete files: This helps reduce clutter and confusion later.

Consider installing a file management tool like:

• WinMerge or Duplicate Cleaner (Windows)
• DMcleaner (Mac) – excellent for spotting duplicate files
• Everything (Windows) – a fast indexing tool for file search

Optional: Repartitioning Without Formatting

In some rare cases, repartitioning your external drive can help you create new partitions without erasing data on existing ones.

On Windows:

• To make the current partition smaller, use Disk Management.
• The unallocated space should be divided into a new partition.
• As desired, format the new partition.

On Mac:

• Use Disk Utility > Partition to add or resize volumes.

⚠️ Warning: Repartitioning carries some risk. Always back up before trying this. If you mistakenly delete a partition, data recovery becomes complex.

What If You Forgot to Back Up Before Formatting? [Data Recovery Method]

If you've already formatted your external hard drive without backing up - don't panic. You may still recover your data using specialized data recovery software, especially if the formatting was a quick format.

Donemax Data Recovery offers easy solution to unformat an external hard drive and get the lost data back.

Step 1. Download and install Donemax Data Recovery on the computer and connect the external hard drive to the same computer.

Step 2. Open Donemax Data Recovery and select the formatted external hard drive.

Step 3. Click on Scan button. Donemax Data Recovery will deeply scan the drive and find all deleted/formatted/lost files.

Step 4. After scanning, you can preview all recoverable files. Then select the wanted files, click on Recover button to save them.

💡 Note: Success depends on whether the data has been overwritten.

Conclusion

Reformatting your external hard drive on Windows or Mac doesn't have to mean losing valuable data. With proper preparation, the process can be smooth, safe, and even beneficial. Whether you're looking to fix file system errors, improve compatibility, or start fresh, the key is to back up your files first, format carefully, and restore your data afterward.

By following this guide, you can confidently reformat your external hard drive without the fear of losing your files - no matter which operating system you use.