How to Repair and Restore Unallocated Space on a USB/SD Card

recover unallocated space on usb drive

Recover unallocated space on USB drive.

Case1: How to recover your pen drive in windows. USB/SD Card Stops Working or stop Showing the actual size of pen drive or any external storage device. Unallocated


The most common reasons are deletion and virus attack.

Suppose, you may accidentally delete the partition on the USB or some application or program is corrupted then this will cause you this type of problem. Recover unallocated space on usb drive

It is also possible that we were doing some operations that required you to delete partitions but you didn’t aware about it. But, it’s not that surprising that virus attacks may bring various negative results, including a USB becoming unallocated.

If you are facing same issue with your Pen Drive and have no intention to perform data recovery. You can create a new partition using the allocated space directly to make the space usable.

My pen drive is 16 Gb but now it is showing only 6kb

recover unallocated space on usb drive

How to Repair it.

usb not showing actual size of USB | recover unallocated space on usb drive

Start the Pen Drive format

  1. Press start button search for cmd and enter
  2. You will see terminal on your screen

using CMD and Diskpart command line to recover USB

Type in terminal –


You will see popup on your screen , continue it by selecting yes option

New terminal (diskpart) will open , this is where you will repair your pen drive

using CMD and Diskpart command line to recover USB

Type these commands one by one

List disk

It will list all disk and partition available on your system

Now select your pen drive

##select the number mentioned in front of your pen drive

select disk 3

Now check once again that you have selected the correct disk, otherwise you will delete the wrong partition fro your system
## * will now be mentioned in front of selected partition

list disk

using CMD and Diskpart command line to recover USB

After confirming it type it


once again


After cleaning process

create partition primary

using CMD and Diskpart command line to recover USB

Case 2: Recovering Pen drive space using Linux (Ubuntu, Centos etc)

  1. Insert the Pen drive
  2. Open Terminal and Type

You will see the list of disk , partition that are mounted on this system

3. The pen drive usually mounted as last because mounting talk place alphabetically so most probably my system been mounted on sda (usb is mounted on sdb)

sudo mkfs.fat /dev/sdb

One message will popup ie. mkfs.fat: Device partition expected, not making filesystem on entire device ‘/dev/sdb’ (use -I to override)

4. Final command will be like this.

sudo mkfs.fat -I /dev/sdb

The Bottom Line

Conclusively, It is easy to recover unallocated space on a USB or any external storage Device. We can fix an unallocated USB/SD card/pen drive by establishing a new volume. No third party tools are necessary to resolve this type of issue USB issue.


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