If you ever try accessing your partitions or flash drive, can't see any files or folders and you have checked the drive's properties and see that there's still data in it, you don't have to worry about it! This is a common problem with Windows users.
To solve this you will have to use these commands:
Open Command, click on Start > Run then type CMD
Type your drive's path letter (d:) press Enter
Then type these commands as it is:
attrib -r -a -s -h /s /d
/s attributes processes matching file in the current folder and subfolders.