disable view attachment for group member?

[geevest.com]

How i can disable view attachment for group member?
im using vb3.7

in usergroup manager (registered user) :
Can Download Attachments : im Check NO
but registered user can open my attachment.
i dont know why but some registered user can open my attachment,

[Lynne]

Are the members who are able to open it also in a secondary group? If so, and the secondary group has permissions, then the Yes will override the No and they will be able to view/download attachments.