bbPress.org

@rumpyhw

To the best of my knowledge you cannot deactivate registration in the admin panel. However, there is a plugin available that will make it so you(the keymaster) will have to approve all registrations.

https://bbpress.org/plugins/topic/approve-user-registration/

Or to protect your forum even further there is also a plugin that allows approval of all posts and topics

https://bbpress.org/plugins/topic/approve-user-registration/

Hope this helps,

RedBull