AOMEI Partition Assistant
Windows Was Unable to Complete the Format | 5 Fixes
There are many factors will cause the message “Windows was unable to complete the format” appear when you format USB flash drive or SD card. Try the 5 targeted fixes to effectively solve the problem!
By Roxanne / Updated on March 11, 2025
When trying to format a USB drive or memory SD card for being unable to access it or something, the format process might fail with an error message saying that Windows was unable to complete the format. This error message is too simple to see any information about what went wrong. Since USB flash drive and SD cards are easy to carry for data storage and transmission, it is important to know how to solve this issue.
Why was Windows unable to format disk
The possible reasons for Windows unable to format pen drive, flash drive, and SD card are various. Here are some common causes:
| Cause | Explanation | Solution |
|---|---|---|
| File system error (RAW or unsupported format) | The storage device is in RAW format or uses an unsupported file system like Ext2/3/4. | Use a third-party formatting tool like AOMEI Partition Assistant to convert the file system or force format it. |
| Bad sectors on USB or SD card | Damaged storage sectors prevent reading/writing operations. | Run disk error checking and a bad sector repair tool. |
| Virus or malware infection | The device is infected, making it inaccessible and unformattable. | Scan and remove the virus using antivirus software. |
| Write-protection or locked by software | The device is locked or write-protected, preventing formatting. | Remove write protection via registry or third-party tools. |
| Physical damage | The device has hardware damage, making it unusable. | Seek professional repair or replace the device. |
For all these reasons behind why Windows was unable to format drive, you may try one or more solutions to fix this problem.
How to fix the Windows was unable to complete the format error?
This part will provide several solutions to solve the Windwows was unable to complete the format on Windows 11, 10, 8/8.1, and 7. Now connect USB drive to computer and follow the step-by-step guide given below:
Note: Formatting a drive will erase all the files on it, be sure to backup important files. If you are not capable of formatting your USB drive (USB flash drive, external hard drive, SD card, pen drive, etc.) in the usual process, then try to fix/format that drive with the following methods. If you format the drive without any backup, you can refer to the guide to recover data from the formatted disk.
Solution 1. Force format drive with powerful partition manager
If Windows was unable to complete the formatting due to a corrupted file system, write-protection, or RAW file syste, you can use powerful and reliable third-party software, AOMEI Partition Assistant. This tool makes formatting easy and supports USB flash drives, SD cards, and other storage devices on Windows 11/10/8/7. It can also format large drives (over 32GB) to FAT32, which Windows usually can't do.
Whether you need to format a drive to FAT32 or NTFS, this software can help. It even allows you to convert a USB flash drive between FAT32 and NTFS without losing data.
It provides many useful features regarding partition and disk management, such as wiping partition, resizing partition, cloning partition, merging partition, moving partition, converting disks between MBR and GPT without deleting partitions.
AOMEI Partition AssistantThe Best Windows Disk Partition Manager and PC Optimizer
After you check and fix the possible errors on the hard drive that Windows unable to format, you can right-click the USB drive in the main interface of AOMEI Partition Assistant, and select the “Format Partition” option to force format the flash drive.
If this is still unable to complete the format, try the "Wipe Hard Drive" option in this freeware to delete all partitions on the hard drive and then create a new partition. If you want to enjoy more advanced features, like recovering lost partitions, erasing SSD drive, migrating OS between MBR and GPT disk, you can choose AOMEI Partition Assistant Professional.
Solution 2. Format with Disk Management
Disk Management is a Windows built in utility that allows you to manage partitions and disks. If your USB drive or SD card is not displayed in File Explorer because it has an unrecognized file system or no file system at all, you can find it in Disk Management. Thus, you can format the drive with the supported file system.
1. Open Disk Management. Right click on Start and select "Disk Management". You can also open it by type “diskmgmt.msc” in the Run box.
2. Right click the drive need formatting and select "Format".
3. In the next screen, select a file system format and click “OK” to start the format.
If the drive is shown as unallocated space without any file system, right click on it and select "New Simple Volume" item. Then you can follow the New Simple Volume Wizard to create a new partition for the flash drive.
Solution 3. Format with Diskpart
Diskpart is also a built in utility that helps you to manage your disks and partitions from the command line. Compared with Disk Management, Diskpart gives you more authorities. If you encounter the Windows unable to complete format issue, you can try this method.
To open Diskpart, you can type “diskpart.exe” in the Run box or run “diskpart” command in an elevated command prompt. Within the Diskpart command utility, you can format a drive with the following commands:
-
list disk
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select disk n (n represents the disk number listed that you want to format)
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clean (this command will delete all the data on the selected disk)
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create partition primary
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format fs=fat32 quick
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assign letter X: (X: represent the drive letter for the USB drive, you can change it based on your needs)
Then the drive will be deleted and reformatted with FAT32 file system. If you want NTFS file system, you can change and use the command: “format fs=ntfs”.
Solution 4. Remove Write Protection
When a hard disk is write-protected, you cannot format the drive or make other changes. If the problem is with the SD card and USB drive, place the switch in the UNLOCK (OFF) position to remove the write protection. Otherwise, use the following command with CMD to remove the write protection:
- Click Windows+X to select the command prompt.
- Type diskpart and press enter.
- Type list disk and press enter.
- Type select disk # and press enter.
- Type properties disk clear read-only.
Solution 5. Cleaning up viruses/malware
Removable storage devices can become infected with viruses when used on computers that are not protected by anti-virus software. Please run an antivirus or Windows Defender scan to remove all possible viruses and malware.
Solution 6. Fix Bad Sectors on the hard drive
Bad sectors are damaged areas on a storage device that can no longer store data properly. When you try to format a drive with bad sectors, Windows may fail and show the error "Windows was unable to complete the format." If you are not sure whether if the bad sectors cause that the drive could not be formatted, you can run AOMEI Partition Assistant to check your USB, SD card or other external drives and repair it.
AOMEI Partition AssistantThe Best Windows Disk Partition Manager and PC Optimizer
Step 1. Download the software, install and launch it. In the main interface, right-click on the drive, in the drop-down menu, select “Check Partition” under the “Advanced” option.
Step 2. In the next screen, check the first option “Check partition and fix errors in this partition by using chkds.exe” and click “OK” to continue.
Summary
Generally, the USB drive or SD card should be formatted as you desire by using the steps above. However, if Windows was unable to complete the format still with those solutions, it is most likely the USB drive has some physical damage that prevents you from accessing it. You can bring it to a repair center to see if people from there can make it workable again by replacing damaged circuits or other damaged parts.
