Let’s say you just installed windows, but told it to use FAT instead of NTFS. Now you have problems because this program won’t work without permissions on the drive. Whoops! Also the Security feature will not work with FAT or FAT32, you will need NTFS for that. There is an easy way to do this:
convert c: /fs:ntfs
Replace c: with your drive name if different. It will warn you about doing this to a mounted drive, tell it N to skip doing this now. Then it will ask you if you want to do this on the next reboot. Say Y. When you reboot, it will convert the drive to NTFS.