Format USB

https://askubuntu.com/questions/22381/how-to-format-a-usb-flash-drive

The Command-Line Way
In case you can't get your device formatted from the GUI, try this way.

Open the Terminal (Ctrl + Alt + T)

List your block storage devices by issuing the command lsblk
Then identify your pen drive by it's SIZE. In my case its /dev/sdb

enter image description here

Erase everything in the pen drive (OPTIONAL):

sudo dd if=/dev/zero of=**/dev/sdb** bs=4k && sync  
Replace /dev/sdb with your corresponding device. This will take some time. It will pretend to be stuck. Just be patient.

for example:

dd if=/dev/zero of=/dev/sdb bs=4k && sync
dd: error writing '/dev/sdb': No space left on device

1984257+0 records in
1984256+0 records out
8127512576 bytes (8.1 GB) copied, 1236.37 s, 6.6 MB/s
Make a new partition table in the device:

sudo fdisk /dev/sdb
Then press letter o to create a new empty DOS partition table.

Make a new partition:

Press letter n to add a new partition. You will be prompted for the size of the partition. Making a primary partition when prompted, if you are not sure.

Then press letter w to write table to disk and exit.

Format your new partition.

See your new partition label with the command lsblk
In my case it is /dev/sdb1
lsblk output

Issue the command below to format the new volume:

sudo mkfs.vfat **/dev/sdb1**  
Please replace /dev/sdb1 with your corresponding device.

Eject the device:

sudo eject /dev/sdb