No files Showing

Good day, I have a WB My Book 4TB in “My PC” it shows that i have 522gb left of free storage but when i open the drive there are no files, when i check hidden files i see a RECYCLER but that folder is empty. i have checked my recycle bin and even did a defrag en checked the HD for errors via properties, i cant seem to figure out where the files went or how to get them back. any advice would be greatly appreciated.