ls -la /Path/To/Users
'/Path/To/Users' only, not '/Path/To/Users/[USERNAME]'.
Copy and paste the result here.
Slightly modified to protect the guity:
$ ls -la Users total 0 drwxr-xr-x 1 root 80 6 Mar 8 2014 . drwxr-xr-x 1 root root 38 Sep 26 2014 .. drwxr-xr-x 1 501 dialout 21 Mar 14 2015 foldername drwxr-xr-x 1 201 201 11 Mar 8 2014 Guest -rw-r--r-- 1 root root 0 Aug 25 2013 .localized drwxrwxrwt 1 root root 11 Dec 5 2015 Shared
drwxr-xr-x 1 201 201 11 Mar 8 2014 Guest
You have to change the user:group with chown as mentioned in my first comment.
sudo chown root:wheel -R Guest
I forgot to mention that failed. This was the output:
chown: invalid group: ‘root:wheel’
(post is archived)