I had the same issue. My 16GB Flash Drive was only showing 64MB as its size and said it was in RAW format. I was having a complete nightmare with it. I tried everything trying to fix it then I came accross this HP USB Disk Storage Format Tool
Install the program and run it as administrator
Select your ScanDisk flash drive
choose Fat32
Tick the Quick Format box
Start formating
If the process fails close the program unplug the flash drive then plug it back in and repeat the process till it formats.
(I had to do this a couple of times). Once its formated successfuly eject the flash drive and then plug it back in again and
you should now see the true size. My Flash drive now shows it to be 14.91GB and its working perfectly.
