Originally posted by alegator
when I do this I see the "Make this folder private" box greyed out (inactive). How can I fix this?
You can't. That feature is only for files and folders under your user profile (e.g. My Documents).
MeEtc has the right idea, although I'd prefer to leave the permissions to the "Administrators" group instead of granting them to a specific user. That should suffice, as you indicated the other user is not an administrator.
If you don't see the "Security" tab, follow the instructions here
. On the "Security" tab, you should already see "Administrators" having "full control". All you need to do is remove permissions for "Authenticated Users" and/or "Users".