[edited update from user]
Ok, I found the missing data! I had each RA log into the computer and check the recycle bin. When one of the RAs logged in, the "data" folder was in the recycle bin. Apparently she had accidentally hit the "Clear All Data" button in MediaLab. But when I or anyone else had logged into the computer, our recycle bins were empty. I am very glad to have recovered the data!