By Emily / Last Updated April 30, 2019

User case

Why does USB flash drive show 0 bytes?

How to fix “USB flash drive showing 0 bytes”?


User case

“Hi, all. Yesterday i connected my USB flash drive to the computer and tried to open it in the Windows Explorer, and it failed every time along with a message which says ‘You need to format it before use it’, but when i click on ‘Format Disk’, another error prompt pops out saying ‘Windows was unable to complete the format’. Finally i found the USB flash drive showing 0 bytes in used, free and capacity space. That drives me crazy! What can i do to get rid of this without losing the important data or files on the USB drive? Thanks in advance.


Why does USB flash drive show 0 bytes?

Many customers may encounter this problem, and it will make things much worse if users have stored a large number of private or important files to the drive. In order to fix such issues as “pendrive showing 0 bytes used space and 0 bytes free space”, we should firstly figure out why that always happen. Main reasons include:

  • Remove the USB flash drive in an improper way or during the process of transferring data.

  • Any partition on this hard drive gets corrupted.

  • The USB drive is infected by some virus, or the MBR gets damaged greatly.

  • USB flash drive has some bad sectors.

  • A sudden or unexpected power failure occurs when the disk is writing data.

  • There are some files which are set as hidden due to some unknown reasons.

  • There is not any recognized partition on the USB drive.

  • Connecting several USB flash drives to the computer at one time or connecting via a bad USB cable.

How to fix “USB flash drive showing 0 bytes”?

After figuring out what leads to this issue, now we focus on how to fix it in an effective way. In general, directly formatting the USB drive is a guaranteed fix but it will cause data loss, so it is not advised when you do care about data saved on the flash drive. If you have done that and the data has been lost, you had better use data recovery software to retrieve lost data on the USB flash drive.

Before proceeding to other solutions, we can firstly try to install this USB again as the following steps:

(1) Connect it to computer.

(2) Right-click “My Computer” --> Manage--> USB Controller -->USB Mass Storage -->Uninstalled.

(3) Remove the USB and re-insert the pendrive into USB port on the computer.

Then, you can try the below solutions to fixing USB showing no media or 0 bytes.

Solution 1. Unplug extra USB drives

If you insert several USB drives simultaneously, which could lead to overloading and affect the normal work of USB drives, please safely eject some to leave one connected. If the USB cable is out of service, you can replace it with a good one so as to ensure the successful usage.

Solution 2. Create a recognized partition

If the USB drive shows unallocated in Disk Management, with no recognized partition, you can create a new partition with maximum size its via Disk Management following the steps:

(1) Right click This PC > Manage>Storage>Disk Management

(2) Right-click the USB drive and choose “New Simple Volume”. Follow the Wizard to create a new partition.

Solution 3. Check whether the data is hidden

If the data are set to be in hidden mode, then the USB may show 0 bytes, so we need to check whether there are some hidden data or not.

(1) Press Windows+R to open Run, and type “cmd” and press Enter. Right click the Command Prompt icon and select "Run as administrator".

(2) Input "attrib –h –r –s /s /d g:\*.*" command and press Enter (replace g: with the drive letter of your USB drive) and press Enter.

After this, you can check your USB flash drive to see whether there are some hidden files or not.

Solution 4. Check and repair bad sectors in USB

If there are some bad sectors in your USB drive, you can repair it via the following method.

(1) Open "Windows Explorer". Right-click on the USB drive, and then select "Properties" from given list.

(2) In the mini window, go to the “Tools” tab and then click on “Check now”.

(3) A new window will pop out, tick both options: “Automatically fix file system errors” and “Scan for and attempt recovery of bad sectors”, and then hit “Start”.

Scan Check USB

(4) It will scan the entire USB disk for errors, fix logical errors, detect bad sectors.

Solution 5. Fix the damaged MBR

If the MBR is damaged by some inappropriate operations, like unplugging the flash drive while it is in operation, you can try to fix by rebuilding it via AOMEI Partition Assistant Standard. It is a free MBR repair tool for Windows 10/8/7/XP/Vista.

(1) Download the freeware, install and run it on Windows computer.

(2) In its main interface, right-click the USB drive and choose “Rebuild MBR”

Rebuild Data Disk MBR

(3) In the dialogue box, choose a proper MBR type for your OS.

Choose MBR Type

(4) Back to main interface and click “Apply” to execute the operation.


If all methods do not take visible effects for the USB drive showing 0 bytes issue and you cannot format 0 bytes USB in Windows native tools, you can also use AOMEI Partition Assistant Standard to format it.


Whenever you meet the issue “USB flash drive showing 0 bytes”, you can try those methods mentioned above. Meanwhile, the AOMEI Partition Assistant could help you a lot in many other disk management problems, such as convert the data disk between MBR and GPT. If you want to convert system disk from MBR to GPT, and vice versa, you need to upgrade to Professional edition.