Hello
There are three reasons why you can not format your USB
Blocked 1) Mode
PenDrive Some come with a lever to make it read only. (Symbolized with a padlock) 2) LowBattery Many Pen Drive are within a short stack, which the exhaustion does not allow formatting the drive. 3) BlockinSome PenDrive not allow direct formatting the drive, needs to be disarmed and jumpear the JP01, then the format should be withdrawn.
Try formatting by Mark System
1. Home
2. In the search box, type CMD
3. Then in the screen symbol prompt, type FORMAT C: (or letter which appears the USB connected)
4. If you want to have more knowledge you can type in FORMAT HELP and press enter
5. Otherwise allows you to format, try to perform a CHKDSK
6. Digita chkdsk / f
Try this and tell me.