Let members reply but reserve new topics for staff

Where: Admin → Members → Groups & permissions → Category access

Before you start

Can reply includes reading/replying; Full access adds new topics. Global group Reply capability must also permit replies. Locked topics remain a separate restriction.

Steps

1. Choose the category.
2. Give Registered Can reply and the relevant staff group Full access.
3. Save, then sign in as an ordinary member.
4. Reply to a staff-created thread and attempt to start another thread.

Verify

An ordinary member replies to an unlocked topic but cannot create a topic in that category.

Troubleshooting

Check global Reply capability, topic lock, approval/trust rules and other additive category grants.