By AOMEI / Last Updated May 25, 2020


“Hello, I have a 4 GB Transcend pen drive, when I open it, Windows gives message that the pen drive is not formatted. And I cannot copy any data into it. When I try to format it, Windows gives message ‘Windows unable to complete the format’. What’s wrong with it? What should I do? Is there any suggestion? Thanks in advance!”

Reasons for Windows unable to format pen drive

Formatting a pen drive, Kingston USB drive, SanDisk SD card, Samsung USB drive, or Transcend pen drive is a quiet easy process. For some reasons, we need to format pen drive into the right file system. But sometimes you may encounter the error “Windows was unable to compete the format”, and you cannot format pen drive successfully. Most reasons that result in this phenomenon can be a virus infection, bad sectors, write-protection or physical damage. If your pen drive has ever been used on a device infected by a virus, it may get virus infected too. As you know, formatting is a writing process. So, you cannot format the pen drive if some of the sectors are damaged or the pen drive is write-protected. If the pen drive has some serious physical damage, you cannot format it too.

How to format pen drive?

How to format pen drive if you encounter the error that Windows unable to complete the format of pen drive? Here provides you three methods to solve this problem.

Method 1. Format pen drive with Disk Management

Disk Management is a disk partition manager provided by Windows. It can help you to format damaged pen drive. You can follow the steps below:

1. Press “Windows” + “R” to open the Run box, type “diskmgmt.msc” and press “Enter” key.

2. Right click the drive you want to format and select “Format”.

3. Then, select a file system you need and click “OK” to start format.

Method 2. Format pen drive with Diskpart

If your pen drive is write protected, you can use Diskpart to remove the write-protection on the pen drive. Before removing the write-protection on the pen drive, you need to check whether there is a physical switch on the pen drive and make sure the switch has been slid to unlock position. If it is still write protected, follow the steps below to remove the write-protection.

1. Press “Windows” + “R” to open the Run box, type “diskpart” in the Run dialog and press “Enter”.

2. Then type the following command and hit “Enter” after each command

list disk

select disk n (here n represent the disk number listed that you want to remove write-protection)

attributes disk

Attributes Diskpart

If you find the “Read-only: Yes”, type “attributes disk clear readonly” command and hit “Enter” to clear read only on pen drive.

3. And then, you can format your pen drive to the file system you need.

4. Here is the example of format pen drive to exFAT. Type the following command and hit “Enter” after each command.

list disk

select disk n (here n is the number of the pen drive)

list partition

select partition # (here # is the number of the partition)

format fs=exfat quick

Format Pendrive

Thus the pen drive has format successful.

Method 3. Format pen drive with third party software

If you think the operation of formating pen drive via built-in tool is complicated, you can turn to a powerful third party software. Compare with other software, here I highly recommend AOMEI Partition Assistant – the best pen drive format tool which provide you many powerful functions like format partition. With the help of this function, you can format your pen drive easily and effectively in Windows 10/8/7, Windows Vista and Windows XP. Let’s see the example of formatting pen drive to NTFS in Windows 7, the specific steps are as follow:

Step 1. Download, install and run AOMEI Partition Assistant. Right click the partition you want to format and select “Format Partition”.

Format Partition

Step 2. Choose the “NTFS” file system in the pop-up window. You can specify “Cluster Size” under file system if you need to. And click “OK” to continue.

Choose File System

Step 3. After that, it will go back to the main interface. Preview the virtual result and click “Apply” > “Proceed” to complete the operation.

Finish Format


Follow these simple steps, you can successfully solve the problem of “Windows unable to format pen drive”. AOMEI Partition Assistant is such a great powerful free partition manager. It can help you easily solve problems such as format partition. And you can also fix the error like current read only yes or cannot format flash drive via this function. Besides formatting partition, it also provides you some advanced features, such as resize/move/delete partition, disk copy, convert to GPT, repair MBR and so on. If you meet the problem like c drive full in Windows 10/8/7, you can upgrade to AOMEI Partition Assistant Professional to solve this problem.