Try moving it to the vault and then formatting the flash drive. If that doesn't work, try a different anti virus - could be something with AVG. I'm not suggesting you have more than one AV installed at the same time, that's a bad idea. But you can download either Avira or Avast then untinstall AVG and install the new one. BTW, both Avira & Avast are generally considered superior to AVG anyway.
