best advice would be to reformat the drive see my pic and use the settings as i have shown then i would check disk as in pic then assign readyboost
and see if this helps. format
Start your computer and plug in the flash drive in the USB port.
Click on "Computer in the start menu. and locate the drive"
right click on the drive and click format and choose your settings check disk for errors
right click on the drive
in error checking click "check now box"