how to stop non registered user to see profile info of members?
Admin CP > Users & Groups > Groups > Edit Guests > Miscellaneous > Un-mark Can View Member list > Save.
it is a group permission
admin panel >> users & groups >> groups >> guests --> forums and posts (tab) --> Viewing Options -->
Can view user profiles? <-- un-tick and save user group
Sorry @.M. is right I read it wrong.