MyBook missing video files

Im new to the Mac world but have slowly figured things out over the past 2 years. Long story short, Ive been moving files from our Mac HDand Ipad to the MyBook HD over the last few days and everything seemed to be going just fine. But then out of nowhere today my wife and I noticed that almost all of our video files were missing. If we clicked the dropdown triangle to open a folder that originally had videos only it would be empty, but all of the folders that had jpeg files in them were all there. Im thoroughly confused and have no idea what to do next, these videos were relatively important to us so any help you guys can provide would be greatly appreciated.

Hello 1stCav, welcome to the WD Community. See if the link below helps.