The 'staff' is infected with a virus, quarantine them.
There is a particular one that does this and infects USB sticks most often, all the files and folder turn into shortcuts, which are actually exes. The actual 'staff' is hiding, or their attributes have been changed to hidden, so, you can't see them but they are there.
Install a good antivirus and get rid of the viruses on the USB and the rig that you plugged the USB stick into.