I did not create this group of users at any point and was surprised to find that several of my files in C drive weren't visible today. when I used open in Microsoft word I could however see the files with a lock against them. I saved one of the invisible files on the desktop and in properties --> Security saw that there was no authenticated user group. However, in the C drive files, the ones which are visible, under properties--> security there is the authenticated user group, along with the others such as administrator etc. I dont remember setting up such an account structure. Any help is deeply appreciated.
Thank you in advance.