How to Fix the “Windows Was Unable to Complete the Format” Error

Windows Was Unable To Complete The Formatting

“Windows was unable to complete the format” is a common error that tends to pop up when you’re trying to format an SD card, USB drive or external HDD. This guide discusses every possible solution to fix the disk and eliminate this annoying error.

Good to know: get up to speed on how to create a Windows 11 USB installer using Command Prompt.

1. Try Formatting the Disk Again

If you’ve encountered the “Windows was unable to complete the format” error while performing a Quick Format option, you should reconnect the drive and try formatting again.

  1. Open File Explorer by pressing the Win + E shortcut.
  2. Right-click the disk you want to format, then choose “Format.”
Clicking on "Format" option from context menu.
  1. Try both quick and non-quick formatting options. You may also want to tick the “Restore device defaults” option, which restores the default settings based on the disk’s manufacturer.
Clicking on the "Restore device default" option in Format window.

FYI: want to make sure your antivirus is working as it should? Learn how to safely test it against real malware.

2. Scan Your Device for Malware

The error may also appear due to a malware infection, which can happen without you even noticing.

  1. Insert your SD card or flash drive into your Windows device.
  2. Launch the Windows Security app. If it’s not working, check the fixes in the guide to resolve the issue before proceeding.
  3. Click the “Virus & Threat protection” option.
Click on "Virus & threat protection" in Windows Security.
  1. Click “Scan options.”
Clicking on "Scan options" button in Virus & threat protection.
  1. Select “Custom scan,” then scroll down and click the “Scan now” option.
Selecting "Custom scan" and then clicking on "Scan now" button.
  1. The File Explorer window will open. Use it to locate the flash drive or SD card that isn’t working.
Locating external disk in File Explorer.
  1. The scan will continue, and the Windows Security app will inform you whether it has removed any malware or viruses. If it informs you, “No current threats detected,” try the next solution.
"No current threats" detected scan message.
  1. Alternatively, use a third-party antivirus app to do the scan. These are some of the best antivirus programs for Windows.

3. Check the Disk and Format It Using the CMD

If the previous solutions didn’t work, it’s time to check the disk and attempt to repair any issue using Command Prompt.

  1. Press Win + S to bring up Windows Search and type “Command Prompt.”
  2. Launch Command Prompt (CMD) as an administrator.
Launching Command Prompt as Administrator
  1. Type the chkdsk command, then press Enter to check the disk’s integrity. Wait a few seconds until the tool fixes any identified issues.
Running chkdsk scan in Command Prompt.
  1. Format the disk using the format H: /fs:ntfs command. Make sure to replace the letter “H” with your personal drive letter. Note that this will format the drive into NTFS. If this is not the correct formatting, you can change it to FAT32.
Commands executed in Command Prompt.

Good to know: check out these free disk partition management tools that are good to have on hand.

4. Use Disk Management

If the previous solutions didn’t get rid of the error, try the Disk Management utility, a comprehensive tool available in Windows.

  1. Type “Disk Management” in Windows Search and select the best match.
Typing "Disk Management" in Windows Search.
  1. Locate the flash drive or SD card you’re trying to format, right-click it, and select “Format.”
Selecting "Format" option from Disk Management utility.
  1. Add a “Volume label” and select the file system for the disk, but leave the “Allocation unit size” as “Default.” We recommend leaving the “Perform a quick format” box unchecked, but it’s not a requirement.
Formatting window with options visible in Disk Management.

5. Check Disk for Write-Protection

If you tried all the solutions described here, and your disk is still not formattable, consider that it might have write-protection status. The easiest way to confirm this suspicion is to try to copy a file onto your SD card or flash drive. If the process fails, you need to remove the write protection to format the disk.

You can remove the write protection through the write-protection switch, which is a physical switch placed on the flash drive or SD card that can be moved up or down to disable or enable this feature. Alternatively, you can follow the next steps if your disk has write-protection and there’s no switch to turn this off.

  1. Run the Command Prompt as an administrator and type diskpart, then press Enter.
Type "diskpart" in Command Prompt.
  1. Type list disk to let the CMD list all your disks, including the one we’re trying to fix. Press Enter.
List of disks in Command Prompt.
  1. Identify the number of the disk by checking the “Disk” column. In our case, it’s “1.” To select the disk, type select disk 1 and press Enter.
Selecting disk in Command Prompt.
  1. Type attributes disk clear readonly and press Enter. This command is used to remove the write protection from the disk.
Removing protection from the disk in Command Prompt.
  1. Now that the write protection is cleared, you can attempt to format the disk again.

Tip: if you want to keep your data safe, learn how to encrypt your USB drive.

6. Make Sure the Disk Isn’t Partitioned

If your flash drive or SD card was partitioned in the past, you may need to remove this partitioning scheme from your disk for it to work correctly.

  1. Retrace steps #1 to #3 from the previous section to select your disk.
  1. Type list partition.
  1. If Command Prompt lists several partitions, type select partition 1 and press Enter.
Select Partition And Delete Parititon
  1. Type delete partition and hit Enter. Repeat the same steps until you delete all partitions.
  1. When you finish deleting partitions, type create partition primary followed by Enter. Your disk will only contain one partition.

Reclaiming Your Removable Drive

The methods outlined here have all been proven to work and eliminate the “Windows was unable to complete the format” error. However, if they failed for you, we encourage you to try the disk on another device. If you are still unable to format, then it’s highly likely you’re looking at a hardware issue. You may want to replace your device with a new flash drive, SD card or external HDD. If you’re instead faced with the “External hard drive access denied” error, this list of suggestions could help you.

All screenshots by Mustafa Ashour.

Mustafa Ashour
Mustafa Ashour

Mustafa is a tech content writer who's a geek at heart. His passion lies in writing about technology, especially software-related topics. He's also interested in digital marketing, business development, and entrepreneurship. He holds a Bachelor's degree in Accounting and Finance.

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