How to Reformat an External Hard Drive on Windows or Mac

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Learn how to completely format a new or old external hard drive on PC
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Formatting a hard drive can change the file system to make it compatible with your computer's operating system and fix any errors on the drive. Be aware that formatting a hard drive erases the drive's contents in the process. Here's how to format an external hard drive on your Mac, Windows 10, or Windows 11 computer.

Quick Steps

  1. Connect your external hard drive to your Windows computer.
  2. Open the File Explorer and right-click the external hard drive.
  3. Click Format… in the pop-up menu.
  4. Click the drop-down menu and select a new File System Format.
  5. Click Start to reformat the hard drive.
Method 1
Method 1 of 2:

Using Windows 10 and 11

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    Insert the drive's USB cable into one of the thin, rectangular slots in your computer's casing.
    • If you're using a desktop computer, USB ports are typically in either the front or the back of the computer's CPU box.
    • Formatting an external hard drive will erase all files on it . If you have important files to keep, make sure you create a backup before continuing.
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    Open the File Explorer . For quick access, right-click the Start menu and select File Explorer .
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    You can find this in the left panel, underneath This PC .
    • You may need to click the arrow next to This PC to expand it.
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    This will be in the right-click menu.
    • A new window will open.
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    Click the drop-down menu and select one of the following options:
    • NTFS - Use this for Windows-only drives.
    • FAT32 - Works on Windows and Mac, but has a storage limit of 32 gigabytes with an individual file size of 4 gigabytes.
    • exFAT (Recommended) - Use this for hard drives you plan on using with multiple devices (Mac, Windows, console, etc.). Similar to FAT32, but has no storage limit.
    • If you've formatted your drive before, check the Quick Format box. Otherwise, uncheck this.
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    Windows will begin formatting your drive.
    • If prompted, click OK .
    • Your external hard drive's files will be erased during this process. It may take a few moments to complete.
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Method 2
Method 2 of 2:

Using Mac

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    Insert the drive's USB cable into one of the thin, rectangular slots in your computer's casing.
    • If you're using an iMac, you may find the USB ports on the side of your keyboard or on the back of the iMac's screen.
    • Not all Macs have USB ports. If you're using a newer Mac that doesn't come with USB ports, you'll need to purchase a USB-C to USB adapter. [1]
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    Open the Spotlight and enter "disk utility" or find the app in your Utilities folder.
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    This is at the top toolbar.
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    It should now have a checkmark next to it.
    • If there's already a checkmark, skip this step.
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    You'll find it in the left panel, under External .
    • Make sure you click the external hard drive name, not the volume within it.
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    This will be in the top-right corner of the Disk Utility window.
    • A pop-up window will open.
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    By default, this may be set to Master Boot Record .
    • For more Format options, select GUID Partition Map .
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    Click the drop-down menu and select one of the following options:
    • Apple File System (APFS) (compatible with macOS 10.13 or later):
      • APFS : uses APFS format without encryption or case-sensitivity
      • APFS (Encrypted): uses APFS format with volume encryption
      • APFS (Case-sensitive): uses APFS format with case-sensitivity for files and folder names
      • APFS (Case-sensitive, Encrypted): uses APFS format with volume encryption and case-sensitivity for files and folder names [2]
    • Mac OS Extended (compatible with macOS 10.12 or earlier):
      • Mac OS Extended (Journaled) : The default Mac format. Only works on Mac.
      • Mac OS Extended (Journaled, Encrypted) : Encrypted version of the default Mac format.
      • Mac OS Extended (Case-sensitive, Journaled) : Version of the default Mac format that treats files with the same name differently if there are case differences (e.g., "file.txt" and "File.txt").
      • Mac OS Extended (Case-sensitive, Journaled, Encrypted) : A combination of the three above formatting options for the Mac format.
    • Windows-compatible formats :
      • MS-DOS (FAT) : Works on both Windows and Mac computers, but has a file size limit of 4 gigabytes.
      • ExFAT (Recommended) : Works on both Windows and Mac computers. Has no storage limit.
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    The external hard drive will be erased and reformatted. It may take a few moments.
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Expert Q&A

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  • Question
    What does it mean to format a hard drive?
    Yaffet Meshesha
    Computer Specialist
    Yaffet Meshesha is a Computer Specialist and the Founder of Techy, a full-service computer pickup, repair, and delivery service. With over eight years of experience, Yaffet specializes in computer repairs and technical support. Techy has been featured on TechCrunch and Time.
    Yaffet Meshesha
    Computer Specialist
    Expert Answer
    Formatting means erasing all of the data off of a storage device so it can be used to store more data. Essentially, it's like a clean slate for your devices, in terms of its storage.
    Thanks! We're glad this was helpful.
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  • Question
    Can I format an external hard drive to work for both Mac and windows? If so, how?
    Community Answer
    Yes, you can. You should format the external drive as either FAT 32 or exFAT. The former has an individual file transfer size limit of 4GB, and the latter doesn't have that limitation.
    Thanks! We're glad this was helpful.
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  • Question
    How do you format an external hard drive which says it can't be formatted?
    Community Answer
    Try removing the external drive's partition in Disk Manager and setting up a new one.
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      References

      1. ↑ https://www.apple.com/shop/product/MJ1M2AM/A/usb-c-to-usb-adapter
      2. ↑ https://support.apple.com/en-au/guide/disk-utility/dsku19ed921c/22..6/mac/14.0
      3. ↑ Yaffet Meshesha. Computer Specialist. Expert Interview. 22 September 2020.

      About This Article

      Article Summary X

      1. Connect the hard drive.
      2. Open File Explorer.
      3. Click This PC .
      4. Click the drive once.
      5. Click the Manage tab.
      6. Click Format .
      7. Select a file system.
      8. Click Start .

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